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

[via llvm-commits]

davidtrevelyan wrote:

What's the plan for enabling the tests for these? In an ideal world we could introduce test coverage for these changes as part of the same PR. Would it make sense to do the following?

1. flip the switch to enable rtsan in the sanitizer common tests, in a separate PR, before this gets merged, and then (once stable)
2. update this PR to also remove `UNSUPPORTED: rtsan` in the tests that this patch fixes.

What do you think would be the best strategy here?

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