linux-aura/webrtc: Disable a couple of tests failing on the bots.

WebRtcBrowserTest.NegotiateUnsupportedVideoCodec and NegotiateNonCryptoCall.

BUG=335916
TBR=erg@chromium.org

Review URL: https://codereview.chromium.org/141423003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245789 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 245789