Shorten autogenerated error message for functions only.

test/mjsunit/error-tostring-omit.js

 // Copyright 2013 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 19 matching lines @@
          "Nam vulputate metus est. Maecenas quis pellentesque eros," +
          "ac mattis augue. Nam porta purus vitae tincidunt blandit." +
          "Aliquam lacus dui, blandit id consectetur id, hendrerit ut" +
          "felis. Class aptent taciti sociosqu ad litora torquent per" +
          "conubia nostra, per inceptos himenaeos. Ut posuere eros et" +
          "tempus luctus. Nullam condimentum aliquam odio, at dignissim" +
          "augue tincidunt in. Nam mattis vitae mauris eget dictum." +
          "Nam accumsan dignissim turpis a turpis duis.";
 }
 
+assertTrue(veryLongString().length > 256);
 
-var re = /omitted/;
+var re = /...<omitted>.../;
 
 try {
-  veryLongString.nonexistentMethod();
+  Number.prototype.toFixed.call(veryLongString);
 } catch (e) {
-  assertTrue(e.message.length < 350);
-  // TODO(verwaest): Proper error message.
-  // assertTrue(re.test(e.message));
+  assertTrue(e.message.length < 256);
+  assertTrue(re.test(e.message));
 }
 
 try {
-  veryLongString().nonexistentMethod();
-} catch (e) {
-  assertTrue(e.message.length < 350);
-  // TODO(verwaest): Proper error message.
-  // assertTrue(re.test(e.message));
-}
-
-try {
   throw Error(veryLongString());
 } catch (e) {
   assertEquals(veryLongString(), e.message);
 }