- Changes some instance fields from VM pointers to VM.  
- Changes some comments to correctly describe code.  

Bug: v8:6635
Change-Id: I9ec93ef0b09d541c966caa6482c5832cd6b1e149
Reviewed-on: https://chromium-review.googlesource.com/584931
Commit-Queue: Bill Budge <bbudge@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46880}