[Extensions] Update PolicyTests to manifest v2

PolicyTests have been updated to manifest v2.
Remove the allowance for manifest v1 extensions.

Bug: 816679
Change-Id: Ifc1db03aa42db2ae367389d4ec3df4efb18573db
Reviewed-on: https://chromium-review.googlesource.com/1026073
Reviewed-by: Julian Pastarmov <pastarmovj@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#553549}
1 file changed