Performance and stability improvements on all platforms.

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

Change-Id: Icd9a2f00ae386f66ce656c90906ffa1dfdfd19dc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1631327
Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/7.6.290@{#1}
Cr-Branched-From: 53c3d747fca39e86e383eefa2944e13d271925d7-refs/heads/master@{#61866}