Revert r9253 because of dartium test failures

vm/flow_graph_builder.h

 // Copyright (c) 2012, 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.
 
 #ifndef VM_FLOW_GRAPH_BUILDER_H_
 #define VM_FLOW_GRAPH_BUILDER_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 96 matching lines @@
   Instruction* entry() const { return entry_; }
   Instruction* exit() const { return exit_; }
 
   bool is_empty() const { return entry_ == NULL; }
   bool is_open() const { return is_empty() || exit_ != NULL; }
 
   void Bailout(const char* reason);
 
   // Append a graph fragment to this graph.  Assumes this graph is open.
   void Append(const EffectGraphVisitor& other_fragment);
-  // Append a single instruction.  Assumes this graph is open. Can not be a
-  // block entry instruction.
+  // Append a single instruction.  Assumes this graph is open.
   void AddInstruction(Instruction* instruction);
 
-  // Append a new block entry to the graph.
-  void AddBlockEntry(BlockEntryInstr* successor);
-
   // Append a 'diamond' branch and join to this graph, depending on which
   // parts are reachable.  Assumes this graph is open.
   void Join(const TestGraphVisitor& test_fragment,
             const EffectGraphVisitor& true_fragment,
             const EffectGraphVisitor& false_fragment);
 
   // Append a 'while loop' test and back edge to this graph, depending on
   // which parts are reachable.  Afterward, the graph exit is the false
   // successor of the loop condition.
   void TieLoop(const TestGraphVisitor& test_fragment,
@@ skipping 197 matching lines @@
   // Output parameters.
   TargetEntryInstr** true_successor_address_;
   TargetEntryInstr** false_successor_address_;
 
   intptr_t condition_token_pos_;
 };
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_BUILDER_H_