Add jingle_unittests to Chromium WebRTC bots.

Also remove tests we don't run from being built:
gpu_ipc_service_unittests
media_unittests
midi_unittests

BUG=717488
NOTRY=True

Review-Url: https://codereview.chromium.org/2854823002
Cr-Commit-Position: refs/heads/master@{#468622}

testing/buildbot/chromium.webrtc.json

@@ -6,9 +6,7 @@
       "content_browsertests",
       "content_unittests",
       "frame_analyzer",
-      "gpu_ipc_service_unittests",
-      "media_unittests",
-      "midi_unittests",
+      "jingle_unittests",
       "remoting_unittests"
     ]
   },
@@ -19,9 +17,7 @@
       "content_browsertests",
       "content_unittests",
       "frame_analyzer",
-      "gpu_ipc_service_unittests",
-      "media_unittests",
-      "midi_unittests",
+      "jingle_unittests",
       "remoting_unittests"
     ]
   },
@@ -32,9 +28,7 @@
       "content_browsertests",
       "content_unittests",
       "frame_analyzer",
-      "gpu_ipc_service_unittests",
-      "media_unittests",
-      "midi_unittests",
+      "jingle_unittests",
       "remoting_unittests"
     ]
   }