Fix a number of tests that incorrectly used assertUnreachable.

test/mjsunit/regress/regress-1170.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 24 matching lines @@
 eval("with({}) { eval('var a = 2') }");
 assertEquals(2, setter_value);
 assertFalse(this.hasOwnProperty("a"));
 
 // Function declarations are treated specially to match Safari. We do
 // not call setters for them.
 eval("function a() {}");
 assertTrue(this.hasOwnProperty("a"));
 
 __proto__.__defineSetter__("b", function(v) { assertUnreachable(); });
+var exception = false;
 try {
   eval("const b = 23");
-  assertUnreachable();
 } catch(e) {
+  exception = true;
   assertTrue(/TypeError/.test(e));
 }
+assertTrue(exception);
+
+exception = false;
 try {
   eval("with({}) { eval('const b = 23') }");
-  assertUnreachable();
 } catch(e) {
+  exception = true;
   assertTrue(/TypeError/.test(e));
 }
+assertTrue(exception);
 
 __proto__.__defineSetter__("c", function(v) { throw 42; });
+exception = false;
 try {
   eval("var c = 1");
-  assertUnreachable();
 } catch(e) {
+  exception = true;
   assertEquals(42, e);
   assertFalse(this.hasOwnProperty("c"));
 }
+assertTrue(exception);