MDEV-11422 rpl.rpl_parallel_optimistic_nobinlog failed in buildbot with "InnoDB: Killing connection failed Deadlock"

innobase_kill_query(): Remove the bogus warning message
(for the valid outcome err==DB_DEADLOCK) that was added in

commit fec844a
Author: Jan Lindström <jan.lindstrom@mariadb.com>
Date:   Tue Sep 6 09:43:16 2016 +0300

    Merge InnoDB 5.7 from mysql-5.7.14.

Also, remove some redundant variables and add a debug assertion for
enforcing the proper outcome of lock_trx_handle_wait().

Author: dr-m

storage/innobase/handler/ha_innodb.cc

@@ -5665,9 +5665,6 @@ innobase_kill_query(
 		/* Cancel a pending lock request if there are any */
 		bool lock_mutex_taken = false;
 		bool trx_mutex_taken = false;
-		bool already_have_lock_mutex = false;
-		bool already_have_trx_mutex = false;
-		dberr_t err = DB_SUCCESS;
 
 		if (trx->lock.wait_lock) {
 			WSREP_DEBUG("Killing victim trx %p BF %d trx BF %d trx_id " IB_ID_FMT " ABORT %d thd %p"
@@ -5681,38 +5678,30 @@ innobase_kill_query(
 		}
 
 		if (!wsrep_thd_is_BF(trx->mysql_thd, FALSE)) {
-			ut_ad(!lock_mutex_own());
 			lock_mutex_enter();
 			lock_mutex_taken = true;
-		} else {
-			already_have_lock_mutex = true;
 		}
 
 		if (trx->abort_type != TRX_WSREP_ABORT) {
-			ut_ad(!trx_mutex_own(trx));
 			trx_mutex_enter(trx);
 			trx_mutex_taken = true;
-		} else {
-			already_have_trx_mutex = true;
 		}
 
-		err = lock_trx_handle_wait(trx,
-			(lock_mutex_taken || already_have_lock_mutex),
-			(trx_mutex_taken || already_have_trx_mutex));
+#ifdef UNIV_DEBUG
+		dberr_t err =
+#endif
+		lock_trx_handle_wait(trx, true, true);
+
+		ut_ad(err == DB_SUCCESS || err == DB_LOCK_WAIT
+		      || err == DB_DEADLOCK);
 
 		if (lock_mutex_taken) {
-			ut_ad(lock_mutex_own());
 			lock_mutex_exit();
 		}
 
 		if (trx_mutex_taken) {
-			ut_ad(trx_mutex_own(trx));
 			trx_mutex_exit(trx);
 		}
-
-		if (err != DB_SUCCESS && err != DB_LOCK_WAIT) {
-			ib::warn() << "Killing connection failed " << ut_strerr(err) << "("<<err<<")";
-		}
 	}
 
 	DBUG_VOID_RETURN;