DevTools: mark execution contexts as isolated worlds

This patch adds the `isIsolatedWorld` bit to the execution context's
aux data.

This is necessary to be able to differentiate between isolated worlds
and other worlds, e.g. worklets.

R=dgozman

Change-Id: I3741b1631f653ffcfaddcba6bf40b229711494dc
Reviewed-on: https://chromium-review.googlesource.com/1173015
Commit-Queue: Andrey Lushnikov <lushnikov@chromium.org>
Reviewed-by: Pavel Feldman <pfeldman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583153}
6 files changed