[llvm] [GlobalISel] emit G_BITCAST in widenScalarMergeValues when DstTy does not match WideTy (PR #203014)

[Petar Avramovic via llvm-commits]

petar-avramovic wrote:

add some ll and mir test, you have some in https://github.com/llvm/llvm-project/pull/212795 

https://github.com/llvm/llvm-project/pull/203014