MDEV-12353 Cleanup: Remove page_rec_get_base_extra_size()

The function page_rec_get_base_extra_size() became dead code in
commit 08ba3887.

storage/innobase/include/page0page.h

@@ -869,15 +869,6 @@ page_get_free_space_of_empty(
 /*=========================*/
 	ulint	comp)	/*!< in: nonzero=compact page format */
 		MY_ATTRIBUTE((const));
-/**********************************************************//**
-Returns the base extra size of a physical record.  This is the
-size of the fixed header, independent of the record size.
-@return REC_N_NEW_EXTRA_BYTES or REC_N_OLD_EXTRA_BYTES */
-UNIV_INLINE
-ulint
-page_rec_get_base_extra_size(
-/*=========================*/
-	const rec_t*	rec);	/*!< in: physical record */
 /************************************************************//**
 Returns the sum of the sizes of the records in the record list
 excluding the infimum and supremum records.

storage/innobase/include/page0page.ic

@@ -563,21 +563,6 @@ page_rec_get_prev(
 	return((rec_t*) page_rec_get_prev_const(rec));
 }
 
-/**********************************************************//**
-Returns the base extra size of a physical record.  This is the
-size of the fixed header, independent of the record size.
-@return REC_N_NEW_EXTRA_BYTES or REC_N_OLD_EXTRA_BYTES */
-UNIV_INLINE
-ulint
-page_rec_get_base_extra_size(
-/*=========================*/
-	const rec_t*	rec)	/*!< in: physical record */
-{
-	compile_time_assert(REC_N_NEW_EXTRA_BYTES + 1
-			    == REC_N_OLD_EXTRA_BYTES);
-	return(REC_N_NEW_EXTRA_BYTES + (ulint) !page_rec_is_comp(rec));
-}
-
 #endif /* UNIV_INNOCHECKSUM */
 
 /************************************************************//**