[llvm] [AMDGPU] Enable StructurizeCFG SkipUniformRegions (PR #206739)

[Jay Foad via llvm-commits]

jayfoad wrote:

> (Will rebase #201675 onto this once this lands.)

FYI I'm getting some more testing run on this PR which I expect to take a few more days at least.

https://github.com/llvm/llvm-project/pull/206739