Test cases require debug_sync enabled

mysql-test/main/flush_read_lock_kill.test

@@ -7,6 +7,7 @@
 --source include/not_embedded.inc
 
 --source include/have_debug.inc
+--source include/have_debug_sync.inc
 
 # This test needs transactional engine as otherwise COMMIT
 # won't block FLUSH TABLES WITH GLOBAL READ LOCK.

mysql-test/main/partition_sync.test

 --source include/have_partition.inc
 --source include/have_debug.inc
+--source include/have_debug_sync.inc
 # Save the initial number of concurrent sessions.
 --source include/count_sessions.inc
 

mysql-test/main/show_explain.test

@@ -2,6 +2,7 @@
 # Tests for SHOW EXPLAIN FOR functionality
 #
 --source include/have_debug.inc
+--source include/have_debug_sync.inc
 --source include/have_innodb.inc
 # Using valgrind can cause 'reap' to fail. See comment below
 --source include/not_valgrind.inc

mysql-test/main/show_explain_non_select.test

@@ -2,6 +2,7 @@
 # SHOW EXPLAIN tests for non-select subqueries
 #
 --source include/have_debug.inc
+--source include/have_debug_sync.inc
 --source include/have_innodb.inc
 --source include/not_embedded.inc
 

mysql-test/main/view_debug.test

 
 --source include/have_debug.inc
+--source include/have_debug_sync.inc
 
 --echo #
 --echo #MDEV-8087:Server crashed in Time_and_counter_tracker::incr_loops