Remove win_asan trybot from PRESUBMIT.py

Removing it since it no longer exists.
See https://codereview.chromium.org/872263002/

TBR=phoglund@webrtc.org
BUG=

Review URL: https://webrtc-codereview.appspot.com/36979004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@8146 4adac7df-926f-26a2-2b94-8c16560cd09d
1 file changed