[Extensions] Update WebstoreInstallerTests to manifest v2

Update WebstoreInstallerTests to manifest v2 and remove the allowance
for manifest v1 extensions.

Repackage the crx used in the webstore_inline_install API tests to be
updated to manifest v2.

Bug: 816679
Change-Id: Id38616cf30c70d886542d5b4d8112c8831372863
Reviewed-on: https://chromium-review.googlesource.com/1017582
Reviewed-by: Karan Bhatia <karandeepb@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#551910}
6 files changed