[llvm] [llvm][LICM] Add flag to control re-association (PR #149829)

[Theodoros Theodoridis via llvm-commits]

thetheodor wrote:

Limiting the multi-use case to FP ops would fix our problematic cases. However, until a proper default solution is found, would it make sense to merge this so that at least we can tweak this behavior whenever it's needed?

https://github.com/llvm/llvm-project/pull/149829