Fix a number of tests that incorrectly used assertUnreachable.

test/mjsunit/regress/regress-1119.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 20 matching lines @@
 __proto__.__defineSetter__("x", function() { hasBeenInvoked = true; });
 __proto__.__defineSetter__("y", function() { throw 'exception'; });
 
 var hasBeenInvoked = false;
 eval("try { } catch (e) { var x = false; }");
 assertTrue(hasBeenInvoked);
 
 var exception;
 try {
   eval("try { } catch (e) { var y = false; }");
-  assertUnreachable();
 } catch (e) {
   exception = e;
 }
 assertEquals('exception', exception);