Implement ES5 erratum: global declarations shadow inherited properties.

test/mjsunit/regress/regress-115452.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 20 matching lines @@
 function foobl() {}
 assertTrue(typeof this.foobl == "function");
 assertTrue(Object.getOwnPropertyDescriptor(this, "foobl").writable);
 
 print(1)
 Object.defineProperty(this, "foobl", {value: 1, writable: false});
 assertSame(1, this.foobl);
 assertFalse(Object.getOwnPropertyDescriptor(this, "foobl").writable);
 
 print(2)
-eval("function foobl() {}");
+try {
+  eval("function foobl() {}");  // Should throw.
+  assertUnreachable();
+} catch (e) {
+  assertInstanceof(e, TypeError);
+}
 assertSame(1, this.foobl);
-assertFalse(Object.getOwnPropertyDescriptor(this, "foobl").writable);
-
-print(3)
-eval("function foobl() {}");
-assertSame(1, this.foobl);
-assertFalse(Object.getOwnPropertyDescriptor(this, "foobl").writable);