[compiler-rt] [compiler-rt][rtsan] Use sanitizer internal allocator during rtsan init to avoid segfault in dlsym (PR #98679)

[via llvm-commits]

davidtrevelyan wrote:

Polite ping FAO @vitalybuka and @MaskRay - your oversight on this PR would be much appreciated, @cjappl and I are just waiting for this and https://github.com/llvm/llvm-project/pull/99437 (also approved) to go in before we submit our next PR for rtsan's frontend in clang. 

Just wanted to also leave a reminder that I don't have commit access, so I will need someone to do the merge for me if there are no further requested changes. 

Many thanks in advance for your time!

https://github.com/llvm/llvm-project/pull/98679