Fixed utf8 encoding/decoding issues in the testing scripts

tools/testing/dart/multitest.dart

 // Copyright (c) 2012, 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 multitest;
 
 import "dart:async";
 import "dart:io";
 import "test_suite.dart";
+import "utils.dart";
 
 // Multitests are Dart test scripts containing lines of the form
 // " [some dart code] /// [key]: [error type]"
 //
 // For each key in the file, a new test file is made containing all
 // the normal lines of the file, and all of the multitest lines containing
 // that key, in the same order as in the source file.  The new test
 // is expected to fail if there is a non-empty error type listed, of
 // type 'compile-time error', 'runtime error', 'static type warning', or
 // 'dynamic type error'.  The type error tests fail only in checked mode.
@@ skipping 31 matching lines @@
 //   aaa
 //   ddd /// 07: static type warning, dynamic type error
 //   eee
 
 void ExtractTestsFromMultitest(Path filePath,
                                Map<String, String> tests,
                                Map<String, Set<String>> outcomes) {
   // Read the entire file into a byte buffer and transform it to a
   // String. This will treat the file as ascii but the only parts
   // we are interested in will be ascii in any case.
-  RandomAccessFile file = new File.fromPath(filePath).openSync(FileMode.READ);
-  List chars = new List(file.lengthSync());
-  int offset = 0;
-  while (offset != chars.length) {
-    offset += file.readListSync(chars, offset, chars.length - offset);
-  }
-  file.closeSync();
-  String contents = new String.fromCharCodes(chars);
-  chars = null;
+  List bytes = new File.fromPath(filePath).readAsBytesSync();
+  String contents = decodeUtf8(bytes);
   int first_newline = contents.indexOf('\n');
   final String line_separator =
       (first_newline == 0 || contents[first_newline - 1] != '\r')
       ? '\n'
       : '\r\n';
   List<String> lines = contents.split(line_separator);
   if (lines.last == '') lines.removeLast();
+  bytes = null;
   contents = null;
   Set<String> validMultitestOutcomes = new Set<String>.from(
       ['compile-time error', 'runtime error',
        'static type warning', 'dynamic type error']);
 
   List<String> testTemplate = new List<String>();
   testTemplate.add(
       '// Test created from multitest named ${filePath.toNativePath()}.');
   // Create the set of multitests, which will have a new test added each
   // time we see a multitest line with a new key.
@@ skipping 174 matching lines @@
     // TestSuite.forDirectory.
     split.removeLast();
   }
   String path = '${generatedTestDir.path}/${split.last}';
   Directory dir = new Directory(path);
   if (!dir.existsSync()) {
     dir.createSync();
   }
   return new Path(new File(path).fullPathSync());
 }