Original CL description:
  [compiler] Delay allocation of heap numbers for deoptimization literals.

  ... until after the main bulk of code generation, which will soon run on a
  different thread.

Bug: v8:6048, chromium:722978
Change-Id: I690c0b009211a2bac60cf06f577720a914c21000
Reviewed-on: https://chromium-review.googlesource.com/507207Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45371}