Reduce ecma_{ref, deref}_object calls while using ecma_builtin_get (#2616)

The following stucture was highly frequented in the code base:

 - Get a builtin object // This operation increases the reference count of the object
 - Use it for create a new object
 - Deref the builtin object

After a builtin has been instantiated there is always at least one reference to "keep it alive",
so increase/decrease the reference count for getting the value only is unnecessary.

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu

jerry-core/ecma/operations/ecma-lex-env.c

@@ -44,8 +44,6 @@ ecma_init_global_lex_env (void)
   JERRY_CONTEXT (ecma_global_lex_env_p) = ecma_create_object_lex_env (NULL,
                                                                       glob_obj_p,
                                                                       ECMA_LEXICAL_ENVIRONMENT_THIS_OBJECT_BOUND);
-
-  ecma_deref_object (glob_obj_p);
 } /* ecma_init_global_lex_env */
 
 /**