[RISCV] Don't call use_nodbg_operands for physical registers in...

[RISCV] Don't call use_nodbg_operands for physical registers in RISCVOptWInstrs hasAllNBitUsers. (#77032)

The ADDIW in the new test case was incorrectly removed due to
incorrectly following the x10 register from the return value back to the
argument. This is due to use_nodbg_operands returning every instruction
that uses a physical register regardless of the data flow.