Add ordering false-positive regressions

[jbuncle]

Summary

• add PATCH regressions for reordered implemented contracts, reordered extended interfaces, and reordered trait precedence fallback lists
• normalise contract identity ordering so semantically identical interface sets compare equal
• normalise trait precedence fallback ordering so insteadof lists compare semantically instead of by source order

Validation

• udocker run -v /data/data/com.termux/files/home/projects/jbuncle/php-autosemver:/app -w /app composer2 sh -lc "find src bin tests -type f -name '*.php' -print0 | xargs -0 -n1 php -l && COVERAGE_MIN=90 COVERAGE_JSON=/tmp/coverage.json COVERAGE_SUMMARY=/tmp/coverage-summary.md phpdbg -qrr tests/coverage.php"