[clang] [UBSAN] Preserve ubsan code with ubsan-unique-traps (PR #83470)

[Vitaly Buka via cfe-commits]

vitalybuka wrote:

> If you are going to remove this feature, I would rather you simply revert the old commit. There is no point leaving the flag in at this point.
> 
> I had explored earlier dealing with the optimization at a later time in the compilation pipeline, but got nowhere and this solution was ideal for my use case, binary size constraints limited any inlining so I never ran into the issue. I appreciate you cleaning this up! :)

Actually I am here because I want to use the flag to avoid merging basic blocks.
We are going to opt-out ubsan checks based on PGO, per basic block hotness https://github.com/llvm/llvm-project/pull/83471 

However I am considering introducing a special intrinsic for that, the this patch will not be needed.


https://github.com/llvm/llvm-project/pull/83470