test262 harness: un-skip stale categories (eval/intl402/property-escapes) so the parity number is honest

[proggeramlug]

Summary

scripts/test262_subset.py hides categories Perry actually handles well, via three skip layers. Three _PATH_SKIP entries (and the features-applicable.txt allowlist) are stale:

skipped category	Perry actual	skip reason (stale)
eval (eval-code + built-ins/eval)	94%	"AOT — can't eval" (eval works; PERRY_ALLOW_EVAL=1 for dynamic)
intl402	78%	"out of scope (no ICU)"
RegExp/property-escapes	87%	"Rust regex crate gap" (\\p{} works)

(RegExp/lookbehind skip is vestigial — that subdir has 0 files. staging stays skipped — genuinely partial.)

The headline ~95.2% is therefore parity over a curated subset, not all of ECMAScript. True parity over everything runnable ≈ 91.8% (~34,305 / 37,384).

Proposed change

1. Remove eval, intl402, RegExp/(?:lookbehind|property-escapes) from _PATH_SKIP (keep staging, module/agent flag-skips).
2. Add intl402 to DEFAULT_DIRS.
3. Add to features-applicable.txt: regexp-unicode-property-escapes + the Intl.* feature tags.
4. Set PERRY_ALLOW_EVAL=1 in the perry compile env so eval-tagged cases run instead of compile-failing.
5. Update the stale comments.

This makes the official number reflect reality (drops the headline to ~92%, honestly). Gaps tracked separately: #5297 (annexB/language).