[compiler-rt] [sanitizer_common] AND signals in BlockSignals instead of deleting (PR #113443)

[Vitaly Buka via llvm-commits]

https://github.com/vitalybuka approved this pull request.

It would be nice to test, but I guess it's hard with lit-test.
Maybe in common unit test.

https://github.com/llvm/llvm-project/pull/113443