build_helper: handle emails containing square brackets

[japaric]

The git API shells out to git rev-list and was directly passing an email string to the command's --author flag. That flag interprets its arguments as a regular expression, meaning that characters like square brackets ([]) in the email string made the command fail to find a commit matching the author e-mail

This commit escapes the email string prior to passing it to git rev-list.

The change is tested in the bootstrap crate because it contains the testing infrastructure to create temporary git repositories.

fixes #140669

[rustbot]

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[rust-log-analyzer]

The job x86_64-gnu-llvm-19 failed! Check out the build log: (web) (plain)

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#18 exporting to docker image format
#18 sending tarball 22.0s done
#18 DONE 33.0s
##[endgroup]
Setting extra environment values for docker:  --env ENABLE_GCC_CODEGEN=1 --env GCC_EXEC_PREFIX=/usr/lib/gcc/
[CI_JOB_NAME=x86_64-gnu-llvm-19]
[CI_JOB_NAME=x86_64-gnu-llvm-19]
debug: `DISABLE_CI_RUSTC_IF_INCOMPATIBLE` configured.
---
sccache: Listening on address 127.0.0.1:4226
##[group]Configure the build
configure: processing command line
configure: 
configure: build.configure-args := ['--build=x86_64-unknown-linux-gnu', '--llvm-root=/usr/lib/llvm-19', '--enable-llvm-link-shared', '--set', 'rust.randomize-layout=true', '--set', 'rust.thin-lto-import-instr-limit=10', '--set', 'build.print-step-timings', '--enable-verbose-tests', '--set', 'build.metrics', '--enable-verbose-configure', '--enable-sccache', '--disable-manage-submodules', '--enable-locked-deps', '--enable-cargo-native-static', '--set', 'rust.codegen-units-std=1', '--set', 'dist.compression-profile=balanced', '--dist-compression-formats=xz', '--set', 'rust.lld=false', '--disable-dist-src', '--release-channel=nightly', '--enable-debug-assertions', '--enable-overflow-checks', '--enable-llvm-assertions', '--set', 'rust.verify-llvm-ir', '--set', 'rust.codegen-backends=llvm,cranelift,gcc', '--set', 'llvm.static-libstdcpp', '--set', 'gcc.download-ci-gcc=true', '--enable-new-symbol-mangling']
configure: build.build          := x86_64-unknown-linux-gnu
configure: target.x86_64-unknown-linux-gnu.llvm-config := /usr/lib/llvm-19/bin/llvm-config
configure: llvm.link-shared     := True
configure: rust.randomize-layout := True
configure: rust.thin-lto-import-instr-limit := 10
---
[RUSTC-TIMING] proc_macro test:false 5.584
[RUSTC-TIMING] test test:false 9.546
    Finished `release` profile [optimized] target(s) in 1m 20s
##[endgroup]
[TIMING] core::build_steps::compile::Std { target: x86_64-unknown-linux-gnu, compiler: Compiler { stage: 1, host: x86_64-unknown-linux-gnu, forced_compiler: true }, crates: [], force_recompile: false, extra_rust_args: ["-Csymbol-mangling-version=v0", "-Cpanic=abort"], is_for_mir_opt_tests: false } -- 80.205
Testing GCC stage1 (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
 Downloading crates ...
  Downloaded boml v0.3.1
   Compiling boml v0.3.1
[RUSTC-TIMING] boml test:false 0.777
   Compiling y v0.1.0 (/checkout/compiler/rustc_codegen_gcc/build_system)
[RUSTC-TIMING] y test:false 2.896
    Finished `release` profile [optimized] target(s) in 4.13s
     Running `/checkout/obj/build/x86_64-unknown-linux-gnu/stage1-codegen/x86_64-unknown-linux-gnu/release/y test --use-backend gcc --gcc-path /checkout/obj/build/x86_64-unknown-linux-gnu/ci-gcc/lib --out-dir /checkout/obj/build/x86_64-unknown-linux-gnu/stage1-tools/cg_gcc --release --mini-tests --std-tests`
`--gcc-path` was provided, ignoring config file. Using `/checkout/obj/build/x86_64-unknown-linux-gnu/ci-gcc/lib` as path for libgccjit
[BUILD] mini_core
[RUSTC-TIMING] mini_core test:false 0.203
[BUILD] example
[AOT] mini_core_hello_world
[RUSTC-TIMING] mini_core_hello_world test:false 0.180
---
    |
note: the function `get_closest_upstream_commit` is defined here
   --> /checkout/src/build_helper/src/git.rs:211:1
    |
211 | / fn get_closest_upstream_commit(
212 | |     git_dir: Option<&Path>,
213 | |     config: &GitConfig<'_>,

[Kobzol]

r? @Kobzol