Move third_party/mojo/src/mojo/public to mojo/public

mojo/public/cpp/test_support/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("../../mojo_sdk.gni")
 
 # GYP version: mojo/public/mojo_public.gyp:mojo_public_test_utils
 mojo_sdk_source_set("test_utils") {
   testonly = true
 
   sources = [
     "lib/test_support.cc",
     "lib/test_utils.cc",
     "test_utils.h",
   ]
 
   deps = [
     "//testing/gtest",
   ]
 
   mojo_sdk_deps = [
     "mojo/public/c/test_support",
     "mojo/public/cpp/system",
   ]
 }