Bug#14547952: DEBUG BUILD FAILS ASSERTION IN RECORDS_IN_RANGE()

ha_innodb::records_in_range(): Remove a debug assertion
that prohibits an open range (full table).

The patch by Jorgen Loland only removed the assertion from the
built-in InnoDB, not from the InnoDB Plugin.

storage/innodb_plugin/handler/ha_innodb.cc

@@ -7438,7 +7438,6 @@ ha_innobase::records_in_range(
 	mem_heap_t*	heap;
 
 	DBUG_ENTER("records_in_range");
-	DBUG_ASSERT(min_key || max_key);
 
 	ut_a(prebuilt->trx == thd_to_trx(ha_thd()));