For the moment, we only pass the global object (the one we are setting up).
A few smaller changes were necessary to avoid failures in
test-object-observe/DontLeakContextOnObserve. Otherwise the global object
would be retained by being context allocated, leading to test failure.

R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/1132513003

Cr-Commit-Position: refs/heads/master@{#28331}