Revert 229087 "Disabling flaky RunMultiThread_DelegatingRenderer..."

Disabled the wrong test.

> Disabling flaky RunMultiThread_DelegatingRenderer_ImplSidePaint.
> 
> Failing flakily on win/mac/linux.
> 
> Build log: http://build.chromium.org/p/chromium.win/builders/Win7%20Tests%20%28dbg%29%281%29/builds/23746
> Flakiness dashboard: http://test-results.appspot.com/dashboards/flakiness_dashboard.html#group=%40ToT%20Chromium&testType=cc_unittests&tests=LayerTreeHostTestStartPageScaleAnimation.RunMultiThread_DelegatingRenderer_ImplSidePaint
> 
> BUG=308435
> R=powei
> TBR=powei
> 
> Review URL: https://codereview.chromium.org/26497008

TBR=dconnelly@chromium.org

Review URL: https://codereview.chromium.org/27683003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229090 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 229090