Rollup merge of #131065 - Voultapher:port-sort-test-suite, r=thomcc

Port sort-research-rs test suite to Rust stdlib tests

This PR is a followup to #124032. It replaces the tests that test the various sort functions in the standard library with a test-suite developed as part of https://github.com/Voultapher/sort-research-rs. The current tests suffer a couple of problems:

- They don't cover important real world patterns that the implementations take advantage of and execute special code for.
- The input lengths tested miss out on code paths. For example, important safety property tests never reach the quicksort part of the implementation.
- The miri side is often limited to `len <= 20` which means it very thoroughly tests the insertion sort, which accounts for 19 out of 1.5k LoC.
- They are split into to core and alloc, causing code duplication and uneven coverage.
- ~~The randomness is tied to a caller location, wasting the space exploration capabilities of randomized testing.~~ The randomness is not repeatable, as it relies on `std::hash::RandomState::new().build_hasher()`.

Most of these issues existed before #124032, but they are intensified by it. One thing that is new and requires additional testing, is that the new sort implementations specialize based on type properties. For example `Freeze` and non `Freeze` execute different code paths.

Effectively there are three dimensions that matter:

- Input type
- Input length
- Input pattern

The ported test-suite tests various properties along all three dimensions, greatly improving test coverage. It side-steps the miri issue by preferring sampled approaches. For example the test that checks if after a panic the set of elements is still the original one, doesn't do so for every single possible panic opportunity but rather it picks one at random, and performs this test across a range of input length, which varies the panic point across them. This allows regular execution to easily test inputs of length 10k, and miri execution up to 100 which covers significantly more code. The randomness used is tied to a fixed - but random per process execution - seed. This allows for fully repeatable tests and fuzzer like exploration across multiple runs.

Structure wise, the tests are previously found in the core integration tests for `sort_unstable` and alloc unit tests for `sort`. The new test-suite was developed to be a purely black-box approach, which makes integration testing the better place, because it can't accidentally rely on internal access. Because unwinding support is required the tests can't be in core, even if the implementation is, so they are now part of the alloc integration tests. Are there architectures that can only build and test core and not alloc? If so, do such platforms require sort testing? For what it's worth the current implementation state passes miri `--target mips64-unknown-linux-gnuabi64` which is big endian.

The test-suite also contains tests for properties that were and are given by the current and previous implementations, and likely relied upon by users but weren't tested. For example `self_cmp` tests that the two parameters `a` and `b` passed into the comparison function are never references to the same object, which if the user is sorting for example a `&mut [Mutex<i32>]` could lead to a deadlock.

Instead of using the hashed caller location as rand seed, it uses seconds since unix epoch / 10, which given timestamps in the CI should be reasonably easy to reproduce, but also allows fuzzer like space exploration.

---

Test run-time changes:

Setup:

```
Linux 6.10
rustc 1.83.0-nightly (f79a912 2024-09-18)
AMD Ryzen 9 5900X 12-Core Processor (Zen 3 micro-architecture)
CPU boost enabled.
```

master: e9df22f

Before core integration tests:

```
$ LD_LIBRARY_PATH=build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/deps/ hyperfine build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/deps/coretests-219cbd0308a49e2f
  Time (mean ± σ):     869.6 ms ±  21.1 ms    [User: 1327.6 ms, System: 95.1 ms]
  Range (min … max):   845.4 ms … 917.0 ms    10 runs

# MIRIFLAGS="-Zmiri-disable-isolation" to get real time
$ MIRIFLAGS="-Zmiri-disable-isolation" ./x.py miri library/core
  finished in 738.44s
```

After core integration tests:

```
$ LD_LIBRARY_PATH=build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/deps/ hyperfine build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/deps/coretests-219cbd0308a49e2f
  Time (mean ± σ):     865.1 ms ±  14.7 ms    [User: 1283.5 ms, System: 88.4 ms]
  Range (min … max):   836.2 ms … 885.7 ms    10 runs

$ MIRIFLAGS="-Zmiri-disable-isolation" ./x.py miri library/core
  finished in 752.35s
```

Before alloc unit tests:

```
LD_LIBRARY_PATH=build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/deps/ hyperfine build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/deps/alloc-19c15e6e8565aa54
  Time (mean ± σ):     295.0 ms ±   9.9 ms    [User: 719.6 ms, System: 35.3 ms]
  Range (min … max):   284.9 ms … 319.3 ms    10 runs

$ MIRIFLAGS="-Zmiri-disable-isolation" ./x.py miri library/alloc
  finished in 322.75s
```

After alloc unit tests:

```
LD_LIBRARY_PATH=build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/deps/ hyperfine build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/deps/alloc-19c15e6e8565aa54
  Time (mean ± σ):      97.4 ms ±   4.1 ms    [User: 297.7 ms, System: 28.6 ms]
  Range (min … max):    92.3 ms … 109.2 ms    27 runs

$ MIRIFLAGS="-Zmiri-disable-isolation" ./x.py miri library/alloc
  finished in 309.18s
```

Before alloc integration tests:

```
$ LD_LIBRARY_PATH=build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/deps/ hyperfine build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/deps/alloctests-439e7300c61a8046
  Time (mean ± σ):     103.2 ms ±   1.7 ms    [User: 135.7 ms, System: 39.4 ms]
  Range (min … max):    99.7 ms … 107.3 ms    28 runs

$ MIRIFLAGS="-Zmiri-disable-isolation" ./x.py miri library/alloc
  finished in 231.35s
```

After alloc integration tests:

```
$ LD_LIBRARY_PATH=build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/deps/ hyperfine build/x86_64-unknown-linux-gnu/stage0-std/x86_64-unknown-linux-gnu/release/deps/alloctests-439e7300c61a8046
  Time (mean ± σ):     379.8 ms ±   4.7 ms    [User: 4620.5 ms, System: 1157.2 ms]
  Range (min … max):   373.6 ms … 386.9 ms    10 runs

$ MIRIFLAGS="-Zmiri-disable-isolation" ./x.py miri library/alloc
  finished in 449.24s
```

In my opinion the results don't change iterative library development or CI execution in meaningful ways. For example currently the library doc-tests take ~66s and incremental compilation takes 10+ seconds. However I only have limited knowledge of the various local development workflows that exist, and might be missing one that is significantly impacted by this change.

library/alloc/src/slice.rs

@@ -19,20 +19,6 @@ use core::cmp::Ordering::{self, Less};
 use core::mem::{self, MaybeUninit};
 #[cfg(not(no_global_oom_handling))]
 use core::ptr;
-#[cfg(not(no_global_oom_handling))]
-use core::slice::sort;
-
-use crate::alloc::Allocator;
-#[cfg(not(no_global_oom_handling))]
-use crate::alloc::Global;
-#[cfg(not(no_global_oom_handling))]
-use crate::borrow::ToOwned;
-use crate::boxed::Box;
-use crate::vec::Vec;
-
-#[cfg(test)]
-mod tests;
-
 #[unstable(feature = "array_chunks", issue = "74985")]
 pub use core::slice::ArrayChunks;
 #[unstable(feature = "array_chunks", issue = "74985")]
@@ -43,6 +29,8 @@ pub use core::slice::ArrayWindows;
 pub use core::slice::EscapeAscii;
 #[stable(feature = "slice_get_slice", since = "1.28.0")]
 pub use core::slice::SliceIndex;
+#[cfg(not(no_global_oom_handling))]
+use core::slice::sort;
 #[stable(feature = "slice_group_by", since = "1.77.0")]
 pub use core::slice::{ChunkBy, ChunkByMut};
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -83,6 +71,14 @@ pub use hack::into_vec;
 #[cfg(test)]
 pub use hack::to_vec;
 
+use crate::alloc::Allocator;
+#[cfg(not(no_global_oom_handling))]
+use crate::alloc::Global;
+#[cfg(not(no_global_oom_handling))]
+use crate::borrow::ToOwned;
+use crate::boxed::Box;
+use crate::vec::Vec;
+
 // HACK(japaric): With cfg(test) `impl [T]` is not available, these three
 // functions are actually methods that are in `impl [T]` but not in
 // `core::slice::SliceExt` - we need to supply these functions for the