Mojo: Enable mojo_shell_tests on Windows (on the bots).

testing/buildbot/chromium.win.json

Index: testing/buildbot/chromium.win.json
diff --git a/testing/buildbot/chromium.win.json b/testing/buildbot/chromium.win.json
index 500ee905aaa4aa8ae3a4603f23d8386d559d6263..3f1fbc4e0478d3d459173c7f7813c3039c126bff 100644
--- a/testing/buildbot/chromium.win.json
+++ b/testing/buildbot/chromium.win.json
@@ -109,6 +109,7 @@
       "mojo_public_system_unittests",
       "mojo_public_utility_unittests",
       "mojo_service_manager_unittests",
+      "mojo_shell_tests",
       "mojo_system_unittests",
       "mojo_view_manager_unittests",
       "sync_unit_tests",
@@ -175,6 +176,7 @@
       "mojo_public_system_unittests",
       "mojo_public_utility_unittests",
       "mojo_service_manager_unittests",
+      "mojo_shell_tests",
       "mojo_system_unittests",
       "mojo_view_manager_unittests",
       "sync_unit_tests",
@@ -239,6 +241,7 @@
       "mojo_public_system_unittests",
       "mojo_public_utility_unittests",
       "mojo_service_manager_unittests",
+      "mojo_shell_tests",
       "mojo_system_unittests",
       "mojo_view_manager_unittests",
       "sync_unit_tests",
@@ -307,6 +310,7 @@
       "mojo_public_system_unittests",
       "mojo_public_utility_unittests",
       "mojo_service_manager_unittests",
+      "mojo_shell_tests",
       "mojo_system_unittests",
       "mojo_view_manager_unittests",
       {"test": "browser_tests", "shard_index": 2, "total_shards": 5}