[llvm] [AMDGPU] Add VOP3 literal testing for GFX1250. NFC. (PR #156496)

[Jay Foad via llvm-commits]

jayfoad wrote:

> Add NFC to the title though.

Done, but I wouldn't normally bother if the title already makes it pretty clear that the patch is just updating tests or fixing typos or something like that.

https://github.com/llvm/llvm-project/pull/156496