Remove Mojo bindings environment.

mojo/public/cpp/utility/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.
 
 source_set("tests") {
   testonly = true
 
   sources = [
     "run_loop_unittest.cc",
   ]
 
   deps = [
-    "//mojo/public/cpp/environment:standalone",
     "//mojo/public/cpp/system",
     "//mojo/public/cpp/test_support:test_utils",
     "//mojo/public/cpp/utility",
     "//testing/gtest",
   ]
 
   # crbug.com/342893
   if (!is_win) {
     sources += [
       "mutex_unittest.cc",
       "thread_unittest.cc",
     ]
   }
 }