[libc++][test] Fixes for `hash<Emplaceable>` and value discarding#126566

frederick-vs-ja merged 1 commit intollvm:mainllvm/llvm-project:mainfrom

frederick-vs-ja:libcxx-test-emplaceable-discardfrederick-vs-ja/llvm-project:libcxx-test-emplaceable-discardCopy head branch name to clipboard