Reset RRT

[BakerSmithA]

Causes issues like below:

Here, SUBI 12 12 1 was transformed into SUBI 17 14 1 by decode step. However, it never got a chance to execute because the pipeline was flushed, but RRT was not restored.

Therefore, the next time the instruction is fetched, it is transformed into SUBI X 17 1, because we are expecting the stack pointer to be stored in register 17. This causes `SUBI instruction to hang until ROB overflows because register 17 is never populated.

To fix, find a way to reset the RRT.