Undo "Don't include an object header for instructions in the text section."

runtime/vm/isolate.h

 // 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.
 
 #ifndef VM_ISOLATE_H_
 #define VM_ISOLATE_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/atomic.h"
@@ skipping 210 matching lines @@
     environment_callback_ = value;
   }
 
   Dart_LibraryTagHandler library_tag_handler() const {
     return library_tag_handler_;
   }
   void set_library_tag_handler(Dart_LibraryTagHandler value) {
     library_tag_handler_ = value;
   }
 
+  void SetupInstructionsSnapshotPage(
+      const uint8_t* instructions_snapshot_buffer);
   void SetupDataSnapshotPage(
       const uint8_t* instructions_snapshot_buffer);
 
   void ScheduleMessageInterrupts();
 
   // Marks all libraries as loaded.
   void DoneLoading();
 
   bool MakeRunnable();
   void Run();
@@ skipping 685 matching lines @@
   intptr_t* spawn_count_;
 
   Dart_IsolateFlags isolate_flags_;
   bool paused_;
   bool errors_are_fatal_;
 };
 
 }  // namespace dart
 
 #endif  // VM_ISOLATE_H_