/usr/lib/mysql-testsuite/suite/stress/ is in percona-server-test-5.6 5.6.22-rel71.0-0ubuntu4.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/mysql-testsuite/suite/stress/include/
/usr/lib/mysql-testsuite/suite/stress/include/ddl.cln
/usr/lib/mysql-testsuite/suite/stress/include/ddl.pre
/usr/lib/mysql-testsuite/suite/stress/include/ddl1.inc
/usr/lib/mysql-testsuite/suite/stress/include/ddl2.inc
/usr/lib/mysql-testsuite/suite/stress/include/ddl3.inc
/usr/lib/mysql-testsuite/suite/stress/include/ddl4.inc
/usr/lib/mysql-testsuite/suite/stress/include/ddl5.inc
/usr/lib/mysql-testsuite/suite/stress/include/ddl6.inc
/usr/lib/mysql-testsuite/suite/stress/include/ddl7.inc
/usr/lib/mysql-testsuite/suite/stress/include/ddl8.inc
/usr/lib/mysql-testsuite/suite/stress/r/
/usr/lib/mysql-testsuite/suite/stress/r/ddl_archive.result
/usr/lib/mysql-testsuite/suite/stress/r/ddl_csv.result
/usr/lib/mysql-testsuite/suite/stress/r/ddl_innodb.result
/usr/lib/mysql-testsuite/suite/stress/r/ddl_memory.result
/usr/lib/mysql-testsuite/suite/stress/r/ddl_myisam.result
/usr/lib/mysql-testsuite/suite/stress/t/
/usr/lib/mysql-testsuite/suite/stress/t/ddl_archive.test
/usr/lib/mysql-testsuite/suite/stress/t/ddl_csv.test
/usr/lib/mysql-testsuite/suite/stress/t/ddl_innodb.test
/usr/lib/mysql-testsuite/suite/stress/t/ddl_memory.test
/usr/lib/mysql-testsuite/suite/stress/t/ddl_myisam.test
/usr/lib/mysql-testsuite/suite/stress/t/wrapper.test