Remove duplicate application cpp files in mojo/application.

mojo/application/public/cpp/tests/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//testing/test.gni")
 
 test("mojo_public_application_unittests") {
   sources = [
     "service_registry_unittest.cc",
   ]
 
   deps = [
-    "//mojo/application/public/cpp:standalone",
+    "//mojo/application/public/cpp",
     "//testing/gtest",
     "//third_party/mojo/src/mojo/edk/test:run_all_unittests",
-    "//third_party/mojo/src/mojo/public/cpp/environment:standalone",
-    "//third_party/mojo/src/mojo/public/cpp/utility",
   ]
 }