Pair some stack ops so that they deal with an even numbers of registers, add
padding around profile entry calls, and delete some unused macro assembler code.

Bug: v8:6644
Change-Id: I5a5529f04738ba2a2fdb1b0d4ee93c567a3c504e
Reviewed-on: https://chromium-review.googlesource.com/686823Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Martyn Capewell <martyn.capewell@arm.com>
Cr-Commit-Position: refs/heads/master@{#48205}