- Avoid private fields (using _xyz instead of #xyz)
- Avoid static fields on classes

These are temporary changes that eventually will be reverted
once FireFox and Safari support it.

Bug: v8:10644
Change-Id: I3d757251eaedef92751970d866882c3d912c7e3e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2464924
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70607}