[llvm] [GlobalIsel] Combine zext of trunc (episode II) (PR #108305)

[Thorsten Schütt via llvm-commits]

tschuett wrote:

https://github.com/llvm/llvm-project/blob/173907b5d77115623f160978a95159e36e05ee6c/llvm/include/llvm/Target/GlobalISel/Combine.td#L761

https://github.com/llvm/llvm-project/pull/108305