[llvm] [llvm][Support][NFC] Disentangle SpecialCaseList parsing and matching (PR #116800)

[kadir çetinkaya via llvm-commits]

kadircet wrote:

see https://github.com/llvm/llvm-project/commit/1fef5e2d7a39038641a893e8f6116762b81b8ca0 for a follow up on how this will be used

https://github.com/llvm/llvm-project/pull/116800