Add corelib tests

test/codegen/corelib/reg_exp_first_match_test.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.
-// Dart test for closures.
 
 import "package:expect/expect.dart";
 
-class A {
-  var field;
-  A(this.field) {}
-}
+// Dart test program for RegExp.firstMatch.
 
-class ClosureTest {
+class RegExpFirstMatchTest {
   static testMain() {
-    var o = new A(3);
-    foo() => o.field++;
-    Expect.equals(3, foo());
-    Expect.equals(4, o.field);
+    Expect.equals('cat', new RegExp("(\\w+)").firstMatch("cat dog")[0]);
+    Expect.equals(null, new RegExp("foo").firstMatch("bar"));
   }
 }
 
 main() {
-  ClosureTest.testMain();
+  RegExpFirstMatchTest.testMain();
 }