[clang] [clang] Add optional pass to remove UBSAN traps using PGO (PR #84214)

[Arthur Eubanks via cfe-commits]

aeubanks wrote:

> > yes, but I'd like to that after we collect feedback from first users
> 
> They are introduced by earlier transformations
> 
> Note: I'd like to have special intrinsic for this optimization. When we have it, we likely don't need this SimplifyCFG.

lgtm with a comment added on why we're adding the extra SimplifyCFG

https://github.com/llvm/llvm-project/pull/84214