Performance and stability improvements on all platforms.

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

Change-Id: I825ebe966980b6c9896b83ed10db846a1db1af8b
Reviewed-on: https://chromium-review.googlesource.com/c/1482990
Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/7.4.198@{#1}
Cr-Branched-From: 7803fa68f48b15534b3dccab5f6eefc9e714e62a-refs/heads/master@{#59785}