Test it it works better to set no read access for a file by using 000 instead of -r

Looks like the trigger.test works that way

mysql-test/t/information_schema.test

@@ -798,9 +798,9 @@ DROP FUNCTION func2;
 #
 create database mysqltest;
 create table mysqltest.t1(a int);
---exec chmod -r $MYSQLTEST_VARDIR/master-data/mysqltest
+--exec chmod 000 $MYSQLTEST_VARDIR/master-data/mysqltest
 select table_schema from information_schema.tables where table_schema='mysqltest';
---exec chmod +r $MYSQLTEST_VARDIR/master-data/mysqltest
+--exec chmod 600 $MYSQLTEST_VARDIR/master-data/mysqltest
 drop database mysqltest;
 
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