Performance and stability improvements on all platforms.

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

Change-Id: Idcb9b8b9b311b8a06f67a3083d7d9900e8455b3e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1605353
Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/7.6.153@{#1}
Cr-Branched-From: e5a5f5ae3cae7bad1652c9c969cfff3dcd2d7225-refs/heads/master@{#61413}