Reversed, indexed and multi-register stores/loads cannot accept SB
inputs. Therefore if one of these Ops is an input to a rule any
pointer that is an argument to that Op cannot be OpSB.

Change-Id: Ib8048362d1c6277122afec0d13a1c905290d69cb
Reviewed-on: https://go-review.googlesource.com/30131
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>