Cleanup CQ configs.

Specifically, remove triggered builders from the list of "launched"
builders.  The new CQ verifier will pick up triggered builders from
the "triggered" section. This eliminates the duplicate specs.

This CL depends on the deployment of the (Google-only) CL:
https://chromereviews.googleplex.com/145077013/

R=phajdan.jr@chromium.org
BUG=436774

Review URL: https://codereview.chromium.org/866293003

Cr-Commit-Position: refs/heads/master@{#313569}

testing/commit_queue/config.json

@@ -91,8 +91,7 @@
               "win_chromium_x64_rel_ng": ["defaulttests"]
             },
             "tryserver.chromium.gpu": {
-                "win_gpu": ["defaulttests"],
-                "win_gpu_triggered_tests": ["defaulttests"]
+                "win_gpu": ["defaulttests"]
             }
         },
         "triggered": {