[llvm] [GlobalISel] Add support to moreElementsVector for G_SEXT, G_ZEXT and G_ANYEXT (PR #85038)

[David Green via llvm-commits]

davemgreen wrote:

> I don't think legal vector arguments to *ext can be 128 bits wide, so this would basically mean clamping them to always be 64 bits wide. I feel this should be a separate patch.

Yeah the legal operations are always essentially that given size. I agree that it's good not to try and solve every problem in a single ticket, and this is a nice step forward. LGTM

https://github.com/llvm/llvm-project/pull/85038