Changing imageFilter GM tests to use drawBitmap instead of drawSprite

The motivation is be able to test the filters with scaled SkPicture playback in isolation from the issues that surround usage of drawSprite
Review URL: https://codereview.appspot.com/7060071

git-svn-id: http://skia.googlecode.com/svn/trunk@7152 2bbb7eff-a529-9590-31e7-b0007b416f81
6 files changed