Revert 287384 "Copy test data to //extensions"

CQ corrupted the PNGs when it landed them. crbug.com/339068

> Copy test data to //extensions
> 
> This copies some assets from //chrome test data into //extensions for use with extensions_unittests.
> 
> BUG=None
> NOTRY=True
> 
> Review URL: https://codereview.chromium.org/443473003

TBR=rockot@chromium.org

Review URL: https://codereview.chromium.org/439723007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@287395 0039d316-1c4b-4281-b951-d872f2087c98

extensions/test/data/image_loader/app.json

-{
-  "name": "test",
-  "version": "1",
-  "manifest_version": 2,
-  "icons": { "16": "16.png",
-             "24": "24.png" }
-}