Convert mus apptests to shelltests

testing/buildbot/chromium.linux.json

Index: testing/buildbot/chromium.linux.json
diff --git a/testing/buildbot/chromium.linux.json b/testing/buildbot/chromium.linux.json
index 80a577ff4071e21a6bc968b994cecd5aa2a28242..72797ac8b46cc68fc8628622c0899bd888aaf82f 100644
--- a/testing/buildbot/chromium.linux.json
+++ b/testing/buildbot/chromium.linux.json
@@ -839,6 +839,9 @@
         "test": "mojo_view_manager_lib_unittests"
       },
       {
+        "test": "mus_ws_unittests"
+      },
+      {
         "swarming": {
           "can_use_on_swarming_builders": true
         },
@@ -932,9 +935,6 @@
         "test": "views_unittests"
       },
       {
-        "test": "window_manager_unittests"
-      },
-      {
         "swarming": {
           "can_use_on_swarming_builders": true
         },
@@ -1618,6 +1618,12 @@
         "swarming": {
           "can_use_on_swarming_builders": true
         },
+        "test": "mus_ws_unittests"
+      },
+      {
+        "swarming": {
+          "can_use_on_swarming_builders": true
+        },
         "test": "nacl_loader_unittests"
       },
       {