Performance and stability improvements on all platforms.

TBR=v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com

Change-Id: I62027a893708fbf1b2ad99b0eac2f509c72a5dfe
Reviewed-on: https://chromium-review.googlesource.com/c/1476305
Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/7.4.191@{#1}
Cr-Branched-From: b6cf4f516b793ee92175af82123617ed40550682-refs/heads/master@{#59656}