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

[Dhruv Chawla via llvm-commits]

dc03-work wrote:

This is the parent PR for https://github.com/llvm/llvm-project/pull/85042, which fixes the codegen issues regarding the large numbers of loads generated for the `vecreduce-add.ll` test case.

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