[llvm] [GlobalISel] Use G_ANYEXT instead of G_ZEXT for shift amount widening (PR #223136)

[Deepak Shirke via llvm-commits]

deepakshirkem wrote:

@davemgreen @arsenm This is my first time updating around 62 tests in a PR, so I’m not really sure if this is the right approach for this PR. Please let me know if this looks fine? If not, I’m happy to close the PR.

https://github.com/llvm/llvm-project/pull/223136