[codex] Expose core Intl constructors

[andrewtdiz]

Summary

• Expose globalThis.Intl as a namespace and wire Intl through HIR/codegen global handling.
• Add focused Intl.NumberFormat, Intl.DateTimeFormat, and Intl.Collator constructor/call-form support, including supportedLocalesOf, format/compare, and resolvedOptions for core locale shapes.
• Add a Node parity fixture covering constructor shape, call forms, locale options, and instance/static methods.

Notes

This is focused compatibility coverage for the core constructors and option shapes exercised by Node parity, not a full ICU implementation.

Validation

• cargo fmt --all -- --check
• git diff --check HEAD~1..HEAD
• ./scripts/check_file_size.sh
• CARGO_BUILD_JOBS=1 CARGO_TARGET_DIR=/tmp/perry-intl-core-check cargo check -q -p perry-runtime -p perry-hir -p perry-codegen
• npx -y node@25 --experimental-strip-types test-parity/node-suite/globals/intl-core.ts
• NODE25_DIR=$(dirname "$(npx -y node@25 -p 'process.execPath')") PATH="$NODE25_DIR:$PATH" CARGO_BUILD_JOBS=1 PERRY_NO_AUTO_OPTIMIZE=1 ./run_parity_tests.sh --suite node-suite --module globals --filter intl-core

Closes #2850.