[RISCV] Branchless lowering for select (and (x , 0x1) == 0), y, (z ^ y) ) and...

[RISCV] Branchless lowering for select (and (x , 0x1) == 0), y, (z ^ y) ) and select (and (x , 0x1) == 0), y, (z | y) )

This code is directly ported from the X86 backend which applies the same rewrite (along with several others). Planning on looking more closely at the other branchless variants from x86 to see if any are worth porting in future changes.

Motivation here is the coremark crc8 routine from https://github.com/eembc/coremark/blob/main/core_util.c#L165. This patch significantly reduces the number of unpredictable branches in the workload.

Differential Revision: https://reviews.llvm.org/D134881