Performance and stability improvements on all platforms.

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

Change-Id: I8f39b81d8a284fdb8aed5cb4ab25dda8e7043851
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1605864
Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/7.6.149@{#1}
Cr-Branched-From: 6644f2b87239dbe8689697aa23a366b5881ec367-refs/heads/master@{#61407}