[Serialization] Avoid repeated hash lookups (NFC)#126429

kazutakahirata merged 1 commit intollvm:mainllvm/llvm-project:mainfrom

kazutakahirata:cleanup_001_repeated_hash_lookups_clang_Serializationkazutakahirata/llvm-project:cleanup_001_repeated_hash_lookups_clang_SerializationCopy head branch name to clipboard