Port f70bb59b

Original Commit Message:

    Includes various fixes and cleanups here and there.

R=ishell@chromium.org, joransiu@ca.ibm.com, michael_dawson@ca.ibm.com, miladfar@ca.ibm.com

LOG=N

Bug: v8:7703, v8:8852
Change-Id: I1e25c6da6677aab64dabc052aee555f534386df7
Reviewed-on: https://chromium-review.googlesource.com/c/1491698Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#59922}