Revert r1380 that is breaking frog.

runtime/vm/code_generator_ia32.cc

Index: runtime/vm/code_generator_ia32.cc
===================================================================
--- runtime/vm/code_generator_ia32.cc	(revision 1381)
+++ runtime/vm/code_generator_ia32.cc	(working copy)
@@ -1389,10 +1389,11 @@
   const Bool& bool_true = Bool::ZoneHandle(Bool::True());
   const Bool& bool_false = Bool::ZoneHandle(Bool::False());
 
-  // All instances are of a subtype of the Object type.
+  // All instances are of type Object.
   const Type& object_type =
       Type::Handle(Isolate::Current()->object_store()->object_type());
   if (type.IsInstantiated() && object_type.IsSubtypeOf(type)) {
+    // All objects are an instance of the Object class.
     __ PushObject(negate_result ? bool_false : bool_true);
     return;
   }