PRESUBMIT: Add Android ARM64 and remove Linux TSan

Update the default trybots due to recent changes in the
trybots available.

TBR=tommi@webrtc.org
BUG=chromium:354539

Review URL: https://webrtc-codereview.appspot.com/21619004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6364 4adac7df-926f-26a2-2b94-8c16560cd09d