[llvm] [VectorCombine] foldShuffleOfBinops - failure to track OperandValueInfo (PR #171934)

[Kavin Gnanapandithan via llvm-commits]

KavinTheG wrote:

- Implemented suggest changes:
  - `Op0Info = TTI.commonOperandInfo(X, Z)` & `Op1Info` above their respective if statements
    - Removed `getOperandInfo`  call within if statements (X == Z and Y == W) as this is already performed within `commonOperandInfo`
  - Simplified `mergeWith`
  - Moved new test cases to the bottom

https://github.com/llvm/llvm-project/pull/171934