Correct file names for tests in tests/language.

tests/language/optimized_string_charcodeat.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.
-
-// Test optimized charCodeAt and array access.
-
-String one_byte = "hest";
-String two_byte = "høns";
-
-int testOneByteCharCodeAt(String x, int i) {
-  int test() {
-    return x.charCodeAt(i);
-  }
-  for (int i = 0; i < 10000; i++) test();
-  return test();
-}
-
-
-int testTwoByteCharCodeAt(String x, int i) {
-  int test() {
-    return x.charCodeAt(i);
-  }
-  for (int i = 0; i < 10000; i++) test();
-  return test();
-}
-
-
-int testConstantStringCharCodeAt(int i) {
-  int test() {
-    return "høns".charCodeAt(i);
-  }
-  for (int i = 0; i < 10000; i++) test();
-  return test();
-}
-
-
-int testConstantIndexCharCodeAt(String x) {
-  int test() {
-    return x.charCodeAt(1);
-  }
-  for (int i = 0; i < 10000; i++) test();
-  return test();
-}
-
-
-main() {
-  Expect.equals(101, testOneByteCharCodeAt(one_byte, 1));
-  Expect.equals(248, testTwoByteCharCodeAt(two_byte, 1));
-  Expect.equals(248, testConstantStringCharCodeAt(1));
-  Expect.equals(101, testConstantIndexCharCodeAt(one_byte));
-}