\U is a Ruby/PCRE-ism, not ECMAScript. Restrict
RegExpEscape.isUnicode()/getUnicode() to lowercase \uHHHH only. No \U
path exists in ParseRegExp.qll's escapedCharacter, and no corpus case
references \U. .expected files unchanged.
Bundle: github/codeql-action codeql-bundle-v2.26.1 (CodeQL CLI 2.26.1).