Fix file_test after changing exception throw from readAsStringSync in File.

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 997 matching lines @@
     var text = new File(name).readAsStringSync();
     Expect.isTrue(text.endsWith("42 bytes."));
     Expect.equals(42, text.length);
     name = getDataFilename("tests/standalone/io/read_as_text.dat");
     text = new File(name).readAsStringSync();
     Expect.equals(6, text.length);
     var expected = [955, 120, 46, 32, 120, 10];
     Expect.listEquals(expected, text.codeUnits);
     // First character is not ASCII. The default ASCII decoder will throw.
     Expect.throws(() => new File(name).readAsStringSync(encoding: ASCII),
-                  (e) => e is FormatException);
+                  (e) => e is FileException);
     // We can use an ASCII decoder that inserts the replacement character.
     var lenientAscii = const AsciiCodec(allowInvalid: true);
     text = new File(name).readAsStringSync(encoding: lenientAscii);
     // Default replacement character is the Unicode replacement character.
     expected = [UNICODE_REPLACEMENT_CHARACTER_RUNE,
                 UNICODE_REPLACEMENT_CHARACTER_RUNE,
                 120, 46, 32, 120, 10];
     Expect.listEquals(expected, text.codeUnits);
     text = new File(name).readAsStringSync(encoding: LATIN1);
     expected = [206, 187, 120, 46, 32, 120, 10];
@@ skipping 283 matching lines @@
       testRenameSync();
       testLastModified();
       asyncEnd();
     });
   }
 }
 
 main() {
   FileTest.testMain();
 }