Create and cache method extraction stub in the ICData.

runtime/vm/il_printer.cc

Index: runtime/vm/il_printer.cc
diff --git a/runtime/vm/il_printer.cc b/runtime/vm/il_printer.cc
index b3410f59672437030e25bc7b112ed3fba2154c82..11763115dc41f987d4e5689bfbf1757582bef79e 100644
--- a/runtime/vm/il_printer.cc
+++ b/runtime/vm/il_printer.cc
@@ -362,7 +362,9 @@ void NativeCallInstr::PrintOperandsTo(BufferFormatter* f) const {
 
 
 void StoreInstanceFieldInstr::PrintOperandsTo(BufferFormatter* f) const {
-  f->Print("%s, ", String::Handle(field().name()).ToCString());
+  f->Print("%s {%"Pd"}, ",
+           String::Handle(field().name()).ToCString(),
+           field().Offset());
   instance()->PrintTo(f);
   f->Print(", ");
   value()->PrintTo(f);