Disable some PPAPI URLLoader tests, they time out.

BUG=95005
NOTREECHECKS=true
NOTRY=true
TBR=dmichael@chromium.org

Review URL: https://codereview.chromium.org/143873015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246379 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246379