Revert of Cast: Re-enable End2EndTest.StartSenderBeforeReceiver (https://codereview.chromium.org/175213004/)

Reason for revert:
The test is failing on all of the windows bots on the Chrome waterfall.
http://build.chromium.org/p/chromium.win/builders/Win7%20Tests%20%281%29/builds/27822/steps/cast_unittests/logs/StartSenderBeforeReceiver

Original issue's description:
> Cast: Re-enable End2EndTest.StartSenderBeforeReceiver
> 
> I was not able to re-produce the non-determism.
> 
> BUG=314233
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=252761

TBR=miu@chromium.org,hubbe@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=314233

Review URL: https://codereview.chromium.org/163883008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252803 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252803