Change the behavior of open on files to not truncate by default

tools/testing/dart/test_suite.dart

 // Copyright (c) 2011, 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("test_suite");
 
 #import("status_file_parser.dart");
 #import("test_runner.dart");
 #import("multitest.dart");
 
@@ skipping 340 matching lines @@
     String dartWrapperFilename = '${tempDir.path}/test.dart';
     if (!isWebTest) {
       // test.dart will import the dart test directly, if it is a library,
       // or indirectly through test_as_library.dart, if it is not.
       String dartLibraryFilename;
       if (isLibraryDefinition) {
         dartLibraryFilename = dartTestFilename;
       } else {
         dartLibraryFilename = 'test_as_library.dart';
         File file = new File('${tempDir.path}/$dartLibraryFilename');
-        RandomAccessFile dartLibrary = file.openSync(writable: true);
+        RandomAccessFile dartLibrary = file.openSync(FileMode.WRITE);
         dartLibrary.writeStringSync(WrapDartTestInLibrary(dartTestFilename));
         dartLibrary.closeSync();
       }
 
       File file = new File(dartWrapperFilename);
-      RandomAccessFile dartWrapper = file.openSync(writable: true);
+      RandomAccessFile dartWrapper = file.openSync(FileMode.WRITE);
       dartWrapper.writeStringSync(DartTestWrapper(
           'dart:dom',
           '../../../tests/isolate/src/TestFramework.dart',
           dartLibraryFilename));
       dartWrapper.closeSync();
     } else {
       return;  // TODO(whesse): Implement client web tests on dartium.
     }
     // Create the HTML file for the test.
     File htmlTestBase = new File('${tempDir.path}/${getHtmlName(filename)}');
-    RandomAccessFile htmlTest = htmlTestBase.openSync(writable: true);
+    RandomAccessFile htmlTest = htmlTestBase.openSync(FileMode.WRITE);
     htmlTest.writeStringSync(GetHtmlContents(
         filename,
         '../../../client/testing/unittest/test_controller.js',
         scriptType,
         '../../../$dartWrapperFilename'));
     htmlTest.closeSync();
 
     for (var vmOptions in optionsFromFile["vmOptions"]) {
       var drtFlags = ['-no-timeout'];
       var dartFlags = ['--enable_asserts', '--enable_type_checks'];
@@ skipping 73 matching lines @@
 
     if (!isWebTest) {
       // test.dart will import the dart test directly, if it is a library,
       // or indirectly through test_as_library.dart, if it is not.
       String dartLibraryFilename;
       if (isLibraryDefinition) {
         dartLibraryFilename = testPath;
       } else {
         dartLibraryFilename = 'test_as_library.dart';
         File file = new File('${tempDir.path}/$dartLibraryFilename');
-        RandomAccessFile dartLibrary = file.openSync(writable: true);
+        RandomAccessFile dartLibrary = file.openSync(FileMode.WRITE);
         dartLibrary.writeStringSync(WrapDartTestInLibrary(testPath));
         dartLibrary.closeSync();
       }  
       
       File file = new File(dartWrapperFilename);
-      RandomAccessFile dartWrapper = file.openSync(writable: true);
+      RandomAccessFile dartWrapper = file.openSync(FileMode.WRITE);
       dartWrapper.writeStringSync(DartTestWrapper(
           domLibraryImport,
           '$dartDir/tests/isolate/src/TestFramework.dart',
           dartLibraryFilename));
       dartWrapper.closeSync();
     } else {
       return;  // TODO(whesse): Implement client web tests on dartium.
     }
     // Create the HTML file for the test.
     File htmlTestBase = new File('${tempDir.path}/${getHtmlName(filename)}');
-    RandomAccessFile htmlTest = htmlTestBase.openSync(writable: true);
+    RandomAccessFile htmlTest = htmlTestBase.openSync(FileMode.WRITE);
     htmlTest.writeStringSync(GetHtmlContents(
         filename,
         '$dartDir/client/testing/unittest/test_controller.js',
         scriptType,
         compiledDartWrapperFilename));
     htmlTest.closeSync();
 
     for (var vmOptions in optionsFromFile["vmOptions"]) {
       List<String> compilerArgs;
       String compilerExecutable = TestUtils.compilerPath(configuration);
@@ skipping 526 matching lines @@
  * $noCrash tests are expected to be flaky but not crash
  * $pass tests are expected to pass
  * $failOk tests are expected to fail that we won't fix
  * $fail tests are expected to fail that we should fix
  * $crash tests are expected to crash that we should fix
  * $timeout tests are allowed to timeout\
 """;
     print(report);
   }
 }