To make code consistent with fef047a4
JSHeapBroker and CompilationDependencies are now being allocated and are using
OptimizedCompilationInfo's zone, which is shared between compiler stages.

Bug: v8:7790
Change-Id: If622ce8b39587ff1c87700ab70e9bd4bc1acc68f
Reviewed-on: https://chromium-review.googlesource.com/1233616Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56066}