[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 80a0ada87d1f4df48a0b60d0f7066780a9f33647..c2421d019efcf51a71de4167346edb0f305fda2c 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;