[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 2a76ad1234b1fc822d9d09c44b91a87a01e21f0e..1f66f08e75ed804203172f444de1ef4d17b29b29 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -6535,9 +6535,8 @@ 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;