Expand Node parity test coverage

[TheHypnoo]

Summary

Expands the curated test-parity/node-suite coverage for the modules that were already under test, without introducing new modules and without expanding object.

This PR adds 184 new Node parity tests across existing module directories:

• assert
• buffer
• console
• diagnostics_channel
• events
• os
• path
• querystring
• string_decoder
• timers
• tty
• url
• util

The suite grows from 611 to 795 tests.

What changed

Added focused edge-case coverage for:

• assertion matching, rejection/throw validation, deep equality, sparse arrays, Map/Set, typed arrays, circular references, symbols, and error causes
• Buffer coercion, allocation, encodings, concat bounds, fill/write behavior, SharedArrayBuffer, inspection, ranges, swaps, and numeric edge cases
• console formatting, Console instances, object labels, grouping, tables, getters, proxy-like shapes, private fields, error causes, and circular/BigInt formatters
• diagnostics channel subscriber behavior, tracing, reentrant publish, import identity, and store shape
• events abort/error handling, capture rejections, listener mutation, symbols, once/on, static listener helpers, and max listener behavior
• OS constants, user info, network interface shape, platform/cpu/load/memory methods, and path-like values
• path POSIX/win32 edge cases, type validation, parsing/formatting, namespaces, glob matching, and normalization
• querystring parsing/stringifying, malformed escapes, custom encoders/decoders, legacy separators, prototype-like keys, and primitive values
• string decoder chunk boundaries, invalid sequences, encoding aliases, stateful writes, and utf16/base64/hex boundaries
• timers promises, abort behavior, object handles, ordering, disposal/refresh/close, clear behavior, and callback arguments
• tty stream/class/isatty shape and coercion cases
• URL, URLSearchParams, file URL helpers, mutation, static parse/canParse, legacy formatting, and encoding behavior
• util formatting, inspect, parseArgs, promisify/callbackify/deprecate, and util.types predicates

Validation performed

New tests were validated against Node 22.15.0 with:

node --experimental-strip-types <new-test-file>

Repository checks run locally:

git diff --check
cargo check -p perry-api-manifest -p perry-hir -p perry-stdlib
cargo build --release -p perry -p perry-runtime -p perry-stdlib

Full node-suite parity run against Perry:

./run_parity_tests.sh --suite=node-suite

Result:

Parity Pass:   679
Parity Fail:   113
Compile Fail:  3
Skipped:       0
Parity Rate:   85.7%

Gaps surfaced by the expanded suite

The expanded suite identifies 116 total parity gaps:

• 113 output/behavior mismatches
• 3 compile failures

By module:

Module	Total tests	Pass	Failures	Rate
util	51	30	21	58.8%
buffer	114	98	16	86.0%
timers	58	45	13	77.6%
console	117	106	11	90.6%
url	48	37	11	77.1%
events	51	41	10	80.4%
assert	63	54	9	85.7%
path	77	68	9	88.3%
os	38	31	7	81.6%
querystring	55	52	3	94.5%
diagnostics_channel	57	55	2	96.5%
string_decoder	34	32	2	94.1%
tty	31	29	2	93.5%
object	1	1	0	100%

Main behavior buckets found:

• util: inspect rendering, util.types predicates, parseArgs, promisify/callbackify/deprecate, format/formatWithOptions options
• buffer: Buffer.from coercion, ArrayBuffer offsets, SharedArrayBuffer, encodings, concat length handling, fill/write validation, inspect constants
• timers: timers/promises abort behavior, interval async iterator, scheduler aborts, timer object methods/disposal, callback this, ordering, one segfault in a promises timeout case
• console: custom Console streams, object label coercion, getter/sorted inspect, class private field output, circular/BigInt formatting
• url: URL mutation/escaping, URLSearchParams constructors and thisArg, file URL Unicode/errors, legacy format/parse edge cases
• events: abort/error behavior, captureRejections, errorMonitor, addAbortListener, symbol/eventNames, once/on semantics
• assert: deep equality for Error cause, Map/Set, partial deep equality, typed arrays, throws/rejects failure behavior
• path: win32/UNC behavior, type validation, normalization, parse, toNamespacedPath, matchesGlob
• os: priority methods, networkInterfaces/loadavg/cpus/userInfo/devNull shapes, dynamic namespace dispatch compile guard
• querystring: custom decoder, missing values, symbol/non-enumerable keys
• diagnostics_channel: subscriber error ordering and traceCallback error-first behavior
• string_decoder: encoding normalization and utf16le compile path
• tty: TTY constructor and color/class shape

Compile failures surfaced:

node-suite/buffer/search/ucs2-and-buffer-needle
node-suite/os/methods/modern-methods
node-suite/string_decoder/utf16le/surrogate-boundaries

Known root causes from local run:

• buffer/search/ucs2-and-buffer-needle: utf16le is not recognized in that Buffer encoding lowering path.
• string_decoder/utf16le/surrogate-boundaries: same utf16le encoding path issue.
• os/methods/modern-methods: dynamic stdlib namespace dispatch (os[name]()) is intentionally blocked by Perry's safety guard.

Suggested follow-up work

This PR intentionally keeps the scope to test coverage. Follow-up implementation work can be split by root cause/module:

1. Quick wins:
   • static-call rewrite or explicit allow comment for os/methods/modern-methods
   • URLSearchParams.forEach(thisArg)
   • console object label coercion
   • Buffer allocation/write/concat validation edge cases
2. High-impact modules:
   • util
   • buffer
   • timers
3. Medium-impact modules:
   • url
   • events
   • console
   • assert
   • path
   • os

Notes

This is opened as a draft because the expanded node-suite intentionally exposes current Perry parity gaps. The PR is intended as a coverage/visibility step before implementation-focused PRs.