This CL inserts NOP instructions a little bit earlier into empty
blocks; this ensures that instructions keep their initial position.

Bug: v8:7327
Change-Id: Idee5269f4fd7fc15c44bda83a2be74e8cff62df8
Reviewed-on: https://chromium-review.googlesource.com/1097078
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53672}