[llvm] [RISCV] Break the (czero_eqz x, (setne x, 0)) -> x combine into 2 combines. (PR #90428)

[Craig Topper via llvm-commits]

topperc wrote:

> Hmm, this patch seems like a NFC(I) change :) If not, please add some tests.

I don't think it's is quite NFC. Removing the setcc in DAGCombine can change use counts and enable other combines that may check that the setcc has only 1 use. I don't have a specific example in mind.

https://github.com/llvm/llvm-project/pull/90428