[heap] Separate out optimized code map processing.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index fd4c852e0781ca525cf76ae56c82f5ed2befff18..6986d00cd7e26e2a0604f8040d68e45f6ce654c9 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -6555,9 +6555,8 @@ class SharedFunctionInfo: public HeapObject {
                         Handle<Object> script_object);
 
   // Layout description of the optimized code map.
-  static const int kNextMapIndex = 0;
-  static const int kSharedCodeIndex = 1;
-  static const int kEntriesStart = 2;
+  static const int kSharedCodeIndex = 0;
+  static const int kEntriesStart = 1;
   static const int kContextOffset = 0;
   static const int kCachedCodeOffset = 1;
   static const int kLiteralsOffset = 2;