This makes e.g., load(file) work within Realm.eval(realm, "load(file)") to load files into that realm.

Bug:

Change-Id: I85738f0dfab621f2a8c9e2703f4ce4b39dd882bf
Reviewed-on: https://chromium-review.googlesource.com/484379Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44887}