Encapsulate compare nil ic_state.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 470d8e89aedf2dcb26fdf92ab1cfbd019925a3cb..991704761960c59ecd7e2dcf5d2552e47bc9c47f 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -4673,10 +4673,6 @@ class Code: public HeapObject {
   // [to_boolean_foo]: For kind TO_BOOLEAN_IC tells what state the stub is in.
   inline byte to_boolean_state();
 
-  // [compare_nil]: For kind COMPARE_NIL_IC tells what state the stub is in.
-  byte compare_nil_state();
-  byte compare_nil_value();
-
   // [has_function_cache]: For kind STUB tells whether there is a function
   // cache is passed to the stub.
   inline bool has_function_cache();