Bug #55284 diagnostics: When UNIV_DEBUG, do not tolerate garbage in

Antelope files in btr_check_blob_fil_page_type(). Unfortunately, we
must keep the check in production builds, because InnoDB wrote
uninitialized garbage to FIL_PAGE_TYPE until fairly recently (5.1.x).

rb://546 approved by Jimmy Yang

storage/innodb_plugin/btr/btr0cur.c

@@ -4169,6 +4169,7 @@ btr_check_blob_fil_page_type(
 	if (UNIV_UNLIKELY(type != FIL_PAGE_TYPE_BLOB)) {
 		ulint	flags = fil_space_get_flags(space_id);
 
+#ifndef UNIV_DEBUG /* Improve debug test coverage */
 		if (UNIV_LIKELY
 		    ((flags & DICT_TF_FORMAT_MASK) == DICT_TF_FORMAT_51)) {
 			/* Old versions of InnoDB did not initialize
@@ -4177,6 +4178,7 @@ btr_check_blob_fil_page_type(
 			a BLOB page that is in Antelope format.*/
 			return;
 		}
+#endif /* !UNIV_DEBUG */
 
 		ut_print_timestamp(stderr);
 		fprintf(stderr,