pfs_instr_config_array elements not deallocated on shutdown

[Laurynas Biveinis]

pfs_instr_config_array array elements not deallocated on shutdown. This is attempted to suppress by valgrind.supp, but not completely. LeakSanitizer run will fail on percona_log_block_size innodb_bug70867 innodb_page_size_func percona_all_o_direct_debug innodb-log-file-size-1 innodb-log-file-size innodb-wl6445-2 tc-heuristic-recover rpl_gtid_mode proxy_protocol_networks_malformed testcases with

=================================================================
==16675==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 21 byte(s) in 1 object(s) allocated from:
    #0 0x7f17748fa54a in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x9854a)
    #1 0xff7f7f in my_malloc /mnt/workspace/percona-server-5.6-asan-param/BUILD_TYPE/debug-asan/Host/ubuntu-xenial-64bit/mysys/my_malloc.c:38
    #2 0x1634b83 in add_pfs_instr_to_array(char const*, char const*) /mnt/workspace/percona-server-5.6-asan-param/BUILD_TYPE/debug-asan/Host/ubuntu-xenial-64bit/storage/perfschema/pfs_server.cc:251
    #3 0x58cccf in mysqld_get_one_option /mnt/workspace/percona-server-5.6-asan-param/BUILD_TYPE/debug-asan/Host/ubuntu-xenial-64bit/sql/mysqld.cc:9198
    #4 0x10256c6 in my_handle_options /mnt/workspace/percona-server-5.6-asan-param/BUILD_TYPE/debug-asan/Host/ubuntu-xenial-64bit/mysys_ssl/my_getopt.cc:817
    #5 0x1025c63 in handle_options /mnt/workspace/percona-server-5.6-asan-param/BUILD_TYPE/debug-asan/Host/ubuntu-xenial-64bit/mysys_ssl/my_getopt.cc:308
    #6 0x5963e5 in handle_early_options() /mnt/workspace/percona-server-5.6-asan-param/BUILD_TYPE/debug-asan/Host/ubuntu-xenial-64bit/sql/mysqld.cc:7263
    #7 0x5a35a3 in mysqld_main(int, char**) /mnt/workspace/percona-server-5.6-asan-param/BUILD_TYPE/debug-asan/Host/ubuntu-xenial-64bit/sql/mysqld.cc:5613
    #8 0x586aae in main /mnt/workspace/percona-server-5.6-asan-param/BUILD_TYPE/debug-asan/Host/ubuntu-xenial-64bit/sql/main.cc:25
    #9 0x7f17726cc82f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)

This is possible to fix by adding/fixing suppressions, but observe that pfs_instr_config_array is already deallocated exactly once since [1]. Thus, it's easy to add a loop that frees its elements too.

[1]:
commit d1e05b0993971fce997a8dbc6dc85af38eff1424
Author: Christopher Powers <email address hidden>
Date: Thu Jan 26 11:49:01 2012 -0600

    Bug#13440472 MANY VALGRIND FAILURES ON DAILY-TRUNK

    Deallocate the array of PFS instrument configuration values during
    server shutdown to avoid Valgrind errors.

[Laurynas Biveinis (laurynas-biveinis)]

https://github.com/percona/percona-server/pull/679, https://github.com/percona/percona-server/pull/680

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PS-3488