[Extensions] Remove legacy test extension

Remove a legacy "adblock.crx" test extension. It was originally added in
2011 in https://codereview.chromium.org/7794011 for some unknown crash
(there was no comment on the CL nor a linked bug to indicate *what*
crash this might be). It is also a manifest v1 extension, which is no
longer supported by chrome. Remove the .crx and the test.

The crx was also used by a policy test, but it appears any crx will do.
Add a simple_with_icon.crx file and use that in place of the old.

Bug: 816679, 387866
Change-Id: Ic3640d8434a2b58a4d4a9d02880db8c9003e94e6
Reviewed-on: https://chromium-review.googlesource.com/1017312
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Reviewed-by: Istiaque Ahmed <lazyboy@chromium.org>
Reviewed-by: Julian Pastarmov <pastarmovj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#552258}
6 files changed