Merge a number of assertion failure fixes to the 3.0 branch.

test/mjsunit/regress/regress-1121.js

 // Copyright 2011 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 14 matching lines @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // See: http://code.google.com/p/v8/issues/detail?id=1121
 
 // Test that changing Array.prototype.__proto__ keeps Array functions working.
 
 Array.prototype.__proto__ = null;
 // pop has custom call generator, so we need some beefier function.
 assertEquals([1, 2, 3], [1, 2, 3].slice());