Remove VideoSendStreamTest.ProducesStats.

This test is covered by EndToEndTests.GetStats and there's no need for a
duplicate test.

BUG=
R=stefan@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/39049004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@8332 4adac7df-926f-26a2-2b94-8c16560cd09d