Driver failure mode fixes (and test cleanup).

pkg/analyzer_cli/test/driver_test.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library analyzer_cli.test.driver;
 
 import 'dart:io';
 
 import 'package:analyzer/plugin/options.dart';
 import 'package:analyzer/source/analysis_options_provider.dart';
@@ skipping 33 matching lines @@
     outSink = savedOutSink;
     errorSink = savedErrorSink;
     exitCode = savedExitCode;
     exitHandler = savedExitHandler;
   }
 
   setUp(() => _setUp());
 
   tearDown(() => _tearDown());
 
+  initializeTestEnvironment();
+
   group('Driver', () {
     group('options', () {
       test('custom processor', () {
         Driver driver = new Driver();
         TestProcessor processor = new TestProcessor();
         driver.userDefinedPlugins = [new TestPlugin(processor)];
         driver.start([
           '--options',
           path.join(testDirectory, 'data/test_options.yaml'),
           path.join(testDirectory, 'data/test_file.dart')
@@ skipping 359 matching lines @@
     this.options = options;
   }
 }
 
 class TestSource implements Source {
   TestSource();
 
   @override
   noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
 }