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

[Thorsten Schütt via llvm-commits]

tschuett wrote:

We have an existing combine zext(trunc) as noted above. With this PR I wanted to do cleanups, i.e., improve the pattern.

And investigate, if we can add an `and` combine for zext(trunc), but the regression are not acceptable.

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