[llvm] [llvm] Disable HandleLLVMOptions in runtimes mode (PR #73031)

[Joseph Huber via llvm-commits]

jhuber6 wrote:

> I've also bisected issues with sanitizer builds back to this commit.
> 
>     * https://github.com/llvm/llvm-project/actions/runs/7014942157/job/19085214160
> 
> 
> This is likely because part of the handling of LLVM_USE_SANITIZER happens in HandleLLVMOptions.

Seems so, anything that appended flags will cause a regression since they are no longer handled. So, things like `LLVM_USE_SANITIZER` or `LLVM_USE_LINKER` aren't adding the flags they normally do. I think the consensus here was that the runtimes should handle this stuff separately. Maybe @ldionne can suggest how to handle this.

For now, we could try to fix it in-place, or we can revert it to get the bots green and we can try again later.

https://github.com/llvm/llvm-project/pull/73031