[Extensions] Update Chrome Manifest Tests to manifest v2

We should (finally) remove support for manifest v1. One of the last
significant dependencies is that a lot of our tests aren't manifest v2
yet.

This CL updates the majority of manifest files under
chrome/test/data/extensions/manifest_tests (which are not usually
named manifest.json).

This CL only modifies files that update cleanly (i.e., no other
test updates necessary). A separate CL will address those.

Bug: 816679
Change-Id: Id8b03de2bd26a70d313e85cf56433e3788686e2d
Reviewed-on: https://chromium-review.googlesource.com/950225
Reviewed-by: Karan Bhatia <karandeepb@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541568}
187 files changed