Using SubtypeTestCache object instead of an array, that way we do not need to patch and can communi…

runtime/vm/code_generator_x64.cc

Index: runtime/vm/code_generator_x64.cc
===================================================================
--- runtime/vm/code_generator_x64.cc	(revision 7292)
+++ runtime/vm/code_generator_x64.cc	(working copy)
@@ -1390,10 +1390,11 @@
   } else {
     __ pushq(raw_null);  // Null instantiator.
   }
+  __ pushq(raw_null);  // SubtypeTestCache not yet supported.
   GenerateCallRuntime(node_id, token_index, kInstanceofRuntimeEntry);
   // Pop the two parameters supplied to the runtime entry. The result of the
   // instanceof runtime call will be left as the result of the operation.
-  __ addq(RSP, Immediate(5 * kWordSize));
+  __ addq(RSP, Immediate(6 * kWordSize));
   if (negate_result) {
     Label negate_done;
     __ popq(RDX);
@@ -1613,10 +1614,11 @@
     __ pushq(raw_null);  // Null instantiator.
   }
   __ PushObject(dst_name);  // Push the name of the destination.
+  __ pushq(raw_null);  // SubtypeTestCache not yet supported.
   GenerateCallRuntime(node_id, token_index, kTypeCheckRuntimeEntry);
   // Pop the parameters supplied to the runtime entry. The result of the
   // type check runtime call is the checked value.
-  __ addq(RSP, Immediate(6 * kWordSize));
+  __ addq(RSP, Immediate(7 * kWordSize));
   __ popq(RAX);
 
   __ Bind(&done);