Remove mysqlnd local_tx functionality

These are not used in-tree and cause unnecessary complexity and
untestable failure modes.

Author: nikic

ext/mysqlnd/mysqlnd.h

@@ -107,8 +107,8 @@ PHPAPI void mysqlnd_debug(const char *mode);
 
 #define mysqlnd_close(conn,is_forced)					(conn)->m->close((conn), (is_forced))
 #define mysqlnd_query(conn, query_str, query_len)		((conn)->data)->m->query((conn)->data, (query_str), (query_len))
-#define mysqlnd_async_query(conn, query_str, query_len)	((conn)->data)->m->send_query((conn)->data, (query_str), (query_len), MYSQLND_SEND_QUERY_EXPLICIT, NULL, NULL)
-#define mysqlnd_reap_async_query(conn)					((conn)->data)->m->reap_query((conn)->data, MYSQLND_REAP_RESULT_EXPLICIT)
+#define mysqlnd_async_query(conn, query_str, query_len)	((conn)->data)->m->send_query((conn)->data, (query_str), (query_len), NULL, NULL)
+#define mysqlnd_reap_async_query(conn)					((conn)->data)->m->reap_query((conn)->data)
 #define mysqlnd_unbuffered_skip_result(result)			(result)->m.skip_result((result))
 
 PHPAPI enum_func_status mysqlnd_poll(MYSQLND **r_array, MYSQLND **e_array, MYSQLND ***dont_poll, long sec, long usec, int * desc_num);