[compiler-rt] [CompilerRT] Add numerical sanitizer (PR #94322)

[Alexander Shaposhnikov via llvm-commits]

alexander-shaposhnikov wrote:

This PR can be committed/reverted independently from https://github.com/llvm/llvm-project/pull/85916 since we've split out the integration tests. In particular, here `check-nsan` would run unit tests only.

https://github.com/llvm/llvm-project/pull/94322