- Fixes Image to not fire an extra onload even when applying clipped image
  prototypes.
- Removes the redundant load listener test from
  ClippedImagePrototypeTest.testApplyToClippedImage().  (there was some
  cross-talk between the various load events triggered by each, and it was
  getting kind of silly.
TBR: rjrjr


git-svn-id: https://google-web-toolkit.googlecode.com/svn/releases/1.6@4576 8db76d5a-ed1c-0410-87a9-c151d255dfc7