[llvm] [X86] mayFoldIntoStore - peek through oneuse bitcase users to find a store node (PR #123366)

[Simon Pilgrim via llvm-commits]

RKSimon wrote:

@abhishek-kaushik22 Thanks for the merge, but I'd prefer to handle these myself in future - I only merge upstream when I know I'm going to have access to my PC for an hour or so afterward in the case of buildbot failures etc. 

https://github.com/llvm/llvm-project/pull/123366