[llvm] [BOLT] Provide backwards compatibility for YAML profile with std::hash (PR #74253)

[Fangrui Song via llvm-commits]

MaskRay wrote:

bolt/test/X86/reader-stale-yaml-std.test introduced by this patch might rely on determinism of `hash_value(StringRef)`, which is not guaranteed.

My Hashing.h change #96282 might cause bolt/test/X86/reader-stale-yaml-std.test to fail: https://github.com/llvm/llvm-project/pull/96282#issuecomment-2198771784
Perhaps the test can be temporarily disabled

https://github.com/llvm/llvm-project/pull/74253