This CL prepare newspace evacuation for parallel execution wrt. to actual
allocations. The priority for allocations is:
* Try to allocate from LAB if objects are below kMaxLabObjectSize
* Allocate directly (synchronized) from newspace for larger objects.
* Fall back to old space allocation (which will be backed by a local compaction
  space in future).

Semantical change: Previously we did fall back to regular new space promotion if
we are OOM in old space. With this CL we fall back to new space promotion, which
could fail because of fragmentation, again leading to an old space allocation
that finally bails into OOM.

Newspace evacuation is still single threaded and requires further changes to
allocation site tracking.

BUG=chromium:524425
LOG=N

Review URL: https://codereview.chromium.org/1487853002

Cr-Commit-Position: refs/heads/master@{#32970}