Run testReadAsText wrapped in createTempDirectory, as it uses the shared temp directory.

tests/standalone/io/file_test.dart

 // Copyright (c) 2013, 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.
 //
 // Dart test program for testing file I/O.
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:collection';
 import 'dart:io';
@@ skipping 1245 matching lines @@
       new File(path).existsSync() ? path : 'runtime/$path';
 
   static String getDataFilename(String path) =>
       new File(path).existsSync() ? path : '../$path';
 
   // Main test entrypoint.
   static testMain() {
     testRead();
     testReadSync();
     testReadStream();
-    testLength();
     testLengthSync();
-    testPosition();
     testPositionSync();
     testOpenDirectoryAsFile();
     testOpenDirectoryAsFileSync();
     testOpenFile();
-    testReadAsBytes();
-    testReadAsBytesEmptyFile();
     testReadAsBytesSync();
     testReadAsBytesSyncEmptyFile();
-    testReadAsText();
-    testReadAsTextEmptyFile();
     testReadAsTextSync();
     testReadAsTextSyncEmptyFile();
-    testReadAsLines();
     testReadAsLinesSync();
-    testReadAsErrors();
-    testLastModified();
     testLastModifiedSync();
 
     createTempDirectory(() {
+      testLength();
       testReadWrite();
       testReadWriteSync();
       testReadWriteNoArgsSync();
       testReadWriteStream();
       testReadEmptyFileSync();
       testReadEmptyFile();
       testReadWriteStreamLargeFile();
+      testReadAsBytes();
+      testReadAsBytesEmptyFile();
+      testReadAsText();
+      testReadAsTextEmptyFile();
+      testReadAsLines();
+      testReadAsErrors();
+      testPosition();
       testTruncate();
       testTruncateSync();
       testCloseException();
       testCloseExceptionStream();
       testBufferOutOfBoundsException();
       testAppend();
       testAppendSync();
       testWriteAppend();
       testOutputStreamWriteAppend();
       testOutputStreamWriteString();
       testWriteVariousLists();
       testDirectory();
       testDirectorySync();
       testWriteStringUtf8();
       testWriteStringUtf8Sync();
       testRename();
       testRenameSync();
+      testLastModified();
     });
   }
 }
 
 main() {
   FileTest.testMain();
 }