Allocate instance closures similarly to regular closures, i.e. without a

runtime/vm/flow_graph_optimizer.cc

Index: runtime/vm/flow_graph_optimizer.cc
===================================================================
--- runtime/vm/flow_graph_optimizer.cc	(revision 33044)
+++ runtime/vm/flow_graph_optimizer.cc	(working copy)
@@ -7263,12 +7263,6 @@
 }
 
 
-void ConstantPropagator::VisitCreateClosure(CreateClosureInstr* instr) {
-  // TODO(kmillikin): Treat closures as constants.
-  SetValue(instr, non_constant_);
-}
-
-
 void ConstantPropagator::VisitAllocateObject(AllocateObjectInstr* instr) {
   SetValue(instr, non_constant_);
 }