[compiler-rt] [sanitizer-common][rtsan] Fix log and stack printing for rtsan (PR #215707)

[Chris Apple via llvm-commits]

cjappl wrote:

> Ah OK - that makes sense. In that case, do you think we should remove `// UNSUPPORTED: rtsan` from the common tests this patch fixes, as part of this PR? Or do you think we should do that separately? If `rtsan` is not in the list of enabled sanitizer projects for the common tests, we're not risking anything more than we would without removing the unsupported flag, right? Please consider this question nonblocking, I don't have strong feelings about it.

Good news is those tests are already not marked UNSUPPORTED (or, are SUPPORTED, to remove the double negative).

The only ones marked UNSUPPORTED in that previous review are the ones that will remain unsupported for a bit while we consider our options :) 

Thanks for being game with the plan that saves me some git bookkeeping, I appreciate it 

https://github.com/llvm/llvm-project/pull/215707