[llvm-branch-commits] [NFC][SpecialCaseList] Move "LongestMatch" logic from WarningsSpecialCaseList into SpecialCaseList (PR #162409)

[Vitaly Buka via llvm-branch-commits]

https://github.com/vitalybuka created https://github.com/llvm/llvm-project/pull/162409

This way we can be more flexible optimizing SpecialCaseList internals.