[llvm] [DenseMap] Optimize find/erase (PR #100517)

[David Peixotto via llvm-commits]

dmpots wrote:

@MaskRay @aganea We are seeing the same test failure on our windows build of LLVM. Only that one test is failing, and a git bisect lead back to this PR. It only fails when running with a release build.  A debug build does not hit the failure.

We are building with `Microsoft (R) C/C++ Optimizing Compiler Version 19.40.33812 for x64`

https://github.com/llvm/llvm-project/pull/100517