Revert 237055 "Disable PPAPI tests that time out on ChromiumOS"

> Disable PPAPI tests that time out on ChromiumOS
> 
> BUG=323144
> TBR=yzshen@chromium.org
> 
> Review URL: https://codereview.chromium.org/85583002

TBR=jochen@chromium.org

Review URL: https://codereview.chromium.org/84743007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237059 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237059