Performance and stability improvements on all platforms.

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

Change-Id: I00d60fe930c455d71ac286266e0c4f41de1bc2da
Reviewed-on: https://chromium-review.googlesource.com/c/1327186
Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/7.2.281@{#1}
Cr-Branched-From: 701136f9ae7365edc522e59d9c967ded3b9c2f06-refs/heads/master@{#57362}