[llvm] [DAG] FoldConstantArithmetic - allow binop folding to work with differing bitcasted constants (PR #94863)

[Simon Pilgrim via llvm-commits]

RKSimon wrote:

Thanks @davemgreen - I've added BE tests to vector-store.ll for completeness but the BuildVector bit extraction code is already fully endian aware.

https://github.com/llvm/llvm-project/pull/94863