This adds support for injecting binding into contexts other than
main based on the context name (AKA isolated world name in Blink
terms). This would simplify a common use case for addBinding in
Puppeteer and other automation tools that use addBinding to expose
a back-channel for extension code running in an isolated world by
making bindings available to such code at an early stage and in a
race-free manner (currently, we can only inject a binding into
specific context after the creation of the context has been reported
to the client, which typically introduces a race with other evals
the client may be running in the context).

Change-Id: I66454954491a47a0c9aa4864f0aace4da2e67d3a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2440984Reviewed-by: Simon Zünd <szuend@chromium.org>
Reviewed-by: Pavel Feldman <pfeldman@chromium.org>
Commit-Queue: Andrey Kosyakov <caseq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70266}