[Extensions] Update Extension 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
extensions/test/data/manifest_tests (which are not usually
named manifest.json).

All these manifests updated cleanly.

Bug: 816679
Change-Id: I5d36f66ac19541b413915a027297ca7cfd359604
Reviewed-on: https://chromium-review.googlesource.com/950231
Reviewed-by: Istiaque Ahmed <lazyboy@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541194}
16 files changed