This is preparation work to re-enable the scheduler: on arm64 some opcodes will
be neutral wrt the stack (JSSP) but will modify the underlying CSP. Identify
those opcode as such until JSSP is removed.

Bug: 
Change-Id: Iae633382c5ed38b01edaec896f2ce44d76931fc8
Reviewed-on: https://chromium-review.googlesource.com/568822Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Rodolph Perfetta <rodolph.perfetta@arm.com>
Cr-Commit-Position: refs/heads/master@{#46946}