[turbofan] Add schedule to visualizer output

src/compiler/schedule.h

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COMPILER_SCHEDULE_H_
 #define V8_COMPILER_SCHEDULE_H_
 
 #include <iosfwd>
 
 #include "src/zone-containers.h"
@@ skipping 249 matching lines @@
   Zone* zone_;
   BasicBlockVector all_blocks_;           // All basic blocks in the schedule.
   BasicBlockVector nodeid_to_block_;      // Map from node to containing block.
   BasicBlockVector rpo_order_;            // Reverse-post-order block list.
   BasicBlock* start_;
   BasicBlock* end_;
 
   DISALLOW_COPY_AND_ASSIGN(Schedule);
 };
 
-std::ostream& operator<<(std::ostream&, const Schedule&);
-
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_SCHEDULE_H_