[runtime] Always normalize prototype maps that aren't marked as 'should be fast' yet

test/mjsunit/fast-prototype.js

Index: test/mjsunit/fast-prototype.js
diff --git a/test/mjsunit/fast-prototype.js b/test/mjsunit/fast-prototype.js
index aa0a62e954e4fadbc6b83cb06af0d8a8f232027b..781e23d4c6e60f3d853bf58d3455677831c2bbd0 100644
--- a/test/mjsunit/fast-prototype.js
+++ b/test/mjsunit/fast-prototype.js
@@ -101,11 +101,12 @@ for (var i = 0; i < 4; i++) {
 
 var x = {a: 1, b: 2, c: 3};
 var o = { __proto__: x };
-assertTrue(%HasFastProperties(x));
+assertFalse(%HasFastProperties(x));
 for (key in x) {
   assertTrue(key == 'a');
   break;
 }
+assertTrue(%HasFastProperties(x));
 delete x.b;
 for (key in x) {
   assertTrue(key == 'a');