[clang] Performance optimizations for function effects (nonblocking attribute etc.) (PR #96844)

[Doug Wyatt via cfe-commits]

dougsonos wrote:

This reduces the compile-time regression introduced by f03cb005eb4ba3c6fb645aca2228e907db8cd452
[Clang] Introduce `nonblocking`/`nonallocating` attributes (#84983)

https://github.com/llvm/llvm-project/pull/96844