[RISCV] Add IsRV32 to the isel pattern for ZIP_RV32/UNZIP_RV32. NFC

I think the i32 in the pattern prevents this from matching on RV64,
but using IsRV32 is safer.

Add tests for RV64 to make sure we don't print zip or unzip
because we incorrectly picked ZIP_RV32/UNZIP_RV32.