Bug#34424: query_cache_debug.test leads to valgrind warnings

Disable the test case.


mysql-test/t/disabled.def:
  Disable query_cache_debug.test.

mysql-test/t/disabled.def

@@ -23,3 +23,4 @@ wait_timeout         : Bug#32801 wait_timeout.test fails randomly
 ctype_create         : Bug#32965 main.ctype_create fails
 status               : Bug#32966 main.status fails
 ps_ddl               : Bug#12093 2007-12-14 pending WL#4165 / WL#4166
+query_cache_debug    : Bug#34424: query_cache_debug.test leads to valgrind warnings