Move the test template to //testing/test.gni (part 2)

third_party/libphonenumber/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/rules.gni")
 import("//third_party/protobuf/proto_library.gni")
 
 proto_library("proto") {
   sources = [
     "src/resources/phonemetadata.proto",
     "src/resources/phonenumber.proto",
   ]
   proto_out_dir = "third_party/libphonenumber/phonenumbers"
 }
 
@@ skipping 80 matching lines @@
   deps = [
     ":libphonenumber_without_metadata",
     "//base",
     "//base/test:run_all_unittests",
     "//base/third_party/dynamic_annotations",
     "//third_party/icu",
     "//testing/gmock",
     "//testing/gtest",
   ]
 }