Add corelib tests

test/codegen/corelib/exception_implementation_test.dart

Index: test/codegen/corelib/exception_implementation_test.dart
diff --git a/test/codegen/language/exception_identity_test.dart b/test/codegen/corelib/exception_implementation_test.dart
similarity index 54%
copy from test/codegen/language/exception_identity_test.dart
copy to test/codegen/corelib/exception_implementation_test.dart
index 2b166078b431732debe3db5c1d0e34ca3c971b73..5df26a7d94a202be24cceb580fd45ce5a7bc72cb 100644
--- a/test/codegen/language/exception_identity_test.dart
+++ b/test/codegen/corelib/exception_implementation_test.dart
@@ -2,25 +2,16 @@
 // 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 exception_implementation_test;
 import "package:expect/expect.dart";
 
-// Test that an object when thrown stays the same.
-
-class A {
-  A();
-}
-
-check(exception) {
+main() {
+  final msg = 1;
   try {
-    throw exception;
-  } catch (e) {
-    Expect.equals(exception, e);
+    throw new Exception(msg);
+    Expect.fail("Unreachable");
+  } on Exception catch (e) {
+    Expect.isTrue(e is Exception);
+    Expect.equals("Exception: $msg", e.toString());
   }
 }
-
-main() {
-  check("str");
-  check(new A());
-  check(1);
-  check(1.2);
-}