Dart: Reorganize files

mojo/dart/test/shared_buffer_finalizer_test.dart

-// Copyright 2015 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 'dart:async';
-import 'dart:isolate';
-import 'dart:typed_data';
-import 'dart:convert';
-
-import 'package:mojo/bindings.dart';
-import 'package:mojo/core.dart';
-import 'package:_mojo_for_test_only/expect.dart';
-
-void mapAndAccess(MojoSharedBuffer bufferHandle, int length) {
-  ByteData mapping = bufferHandle.map(0, length, MojoSharedBuffer.mapFlagNone);
-  if (bufferHandle.status != MojoResult.kOk) {
-    throw "Bad shared buffer map: ${bufferHandle.status}";
-  }
-
-  Uint8List copy = new Uint8List(length);
-  copy[0] = mapping.getUint8(0);
-
-  bufferHandle.close();
-}
-
-int main() {
-  MojoSharedBuffer bufferHandle;
-
-  for (int i = 0; i < 1000; i++) {
-    bufferHandle = new MojoSharedBuffer.create(30000);
-    mapAndAccess(bufferHandle, 30000);
-  }
-
-  return 0;
-}