[llvm] [RISCV] Optimize (and (icmp x, 0, eq), (icmp y, 0, eq)) utilizing zicond extension (PR #166469)

[Ryan Buchner via llvm-commits]

bababuck wrote:

Thanks for the feedback! Address the above comments in the latest push:
- Now using `Use Subtarget.hasCZEROLike()` instead of `Subtarget.hasStdExtZicond() || Subtarget.hasVendorXVentanaCondOps()`
- Removed references to SDValues
- Rename `reduceANDOfSetCC()` to `combineANDOfSetCCToCZERO()`

https://github.com/llvm/llvm-project/pull/166469