Remove mojo::edk::test::ScopedIPCSupport

mojo/edk/test/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")
 
 static_library("test_support") {
   testonly = true
   sources = [
     "mojo_test_base.cc",
     "mojo_test_base.h",
-    "scoped_ipc_support.cc",
-    "scoped_ipc_support.h",
     "test_utils.h",
     "test_utils_posix.cc",
     "test_utils_win.cc",
   ]
 
   if (!is_ios) {
     sources += [
       "multiprocess_test_helper.cc",
       "multiprocess_test_helper.h",
     ]
@@ skipping 100 matching lines @@
     "//mojo/public/c/system/tests:perftests",
   ]
 }
 
 test("mojo_public_system_unittests") {
   deps = [
     ":run_all_unittests",
     "//mojo/public/cpp/system/tests",
   ]
 }