Revert r38116 because of crashes.

runtime/vm/flow_graph_optimizer.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/flow_graph_optimizer.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
 #include "vm/cpu.h"
 #include "vm/dart_entry.h"
@@ skipping 7844 matching lines @@
 // cannot have constant values.
 void ConstantPropagator::VisitStoreContext(StoreContextInstr* instr) { }
 
 
 void ConstantPropagator::VisitCheckStackOverflow(
     CheckStackOverflowInstr* instr) { }
 
 
 void ConstantPropagator::VisitCheckClass(CheckClassInstr* instr) { }
 
-void ConstantPropagator::VisitCheckClassId(CheckClassIdInstr* instr) { }
-
 void ConstantPropagator::VisitGuardFieldClass(GuardFieldClassInstr* instr) { }
 
 void ConstantPropagator::VisitGuardFieldLength(GuardFieldLengthInstr* instr) { }
 
 void ConstantPropagator::VisitCheckSmi(CheckSmiInstr* instr) { }
 
 
 void ConstantPropagator::VisitCheckEitherNonSmi(
     CheckEitherNonSmiInstr* instr) { }
 
@@ skipping 1908 matching lines @@
   }
 
   // Insert materializations at environment uses.
   for (intptr_t i = 0; i < exits.length(); i++) {
     CreateMaterializationAt(exits[i], alloc, alloc->cls(), *slots);
   }
 }
 
 
 }  // namespace dart