Mark null and undefined as undetectable, and use it to handle abstract equality comparison in the g…

test/mjsunit/typeof.js

Index: test/mjsunit/typeof.js
diff --git a/test/mjsunit/typeof.js b/test/mjsunit/typeof.js
index 8aa0ab1c3d8c767397d27f34e1c4790b483f9a6b..864f1cfdb6bf739e1e4e3bd0ccadb77dd6ad10c9 100644
--- a/test/mjsunit/typeof.js
+++ b/test/mjsunit/typeof.js
@@ -35,3 +35,5 @@ assertFalse(typeof r == 'function');
 
 function test(x, y) { return x == y; }
 assertTrue(test('object', typeof r));
+
+assertFalse(typeof null == "undefined");