[llvm] [GlobalISel] Combine G_UNMERGE_VALUES with anyext and build vector (PR #112370)

[Thorsten Schütt via llvm-commits]

tschuett wrote:

As shown in the summary, I found this pattern with grepping. I don't know where the LegalizerHelper creates this pattern.

https://github.com/llvm/llvm-project/pull/112370