Revert 287352 "Add test data for extensions ImageLoaderTest"

The PNG files are corrupt.

> Add test data for extensions ImageLoaderTest
> 
> Binary data for https://codereview.chromium.org/439023002/
> 
> BUG=397164
> TEST=none
> TBR=yoz@chromium.org
> NOTRY=true
> 
> Review URL: https://codereview.chromium.org/433583004

TBR=jamescook@chromium.org

Review URL: https://codereview.chromium.org/430823003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@287367 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" }
-}