MDEV-18908: Remove galera and wsrep suites from default run suites in mtr

Idea is that many users do not install galera library and do not want
to unnecessary run galera and wsrep suites. Furthermore, failures on
these suites disturb development as buildbot shows red failing column
and causes unnecessary work for those who do not care galera tests.
There will be other way to run these suites on buildbot.

mysql-test/mysql-test-run.pl

@@ -195,8 +195,6 @@ my @DEFAULT_SUITES= qw(
     sys_vars-
     unit-
     vcol-
-    wsrep-
-    galera-
   );
 my $opt_suites;