Remove the Android generator.

buildbot/commit_queue/cq_config.json

 {
     "trybots": {
         "launched": {
             "tryserver.nacl": {
                 "gyp-presubmit": ["defaulttests"],
-                "gyp-android": ["defaulttests"],
                 "gyp-linux": ["defaulttests"],
                 "gyp-mac": ["defaulttests"],
                 "gyp-win32": ["defaulttests"],
                 "gyp-win64": ["defaulttests"]
             }
         },
         "triggered": {
         }
     }
 }