mtr: don't disable tests in suite.pm unnecessary

only those tests should be disabled in suite.pm that
cannot be disabled from mysqltest files (e.g. when the
server is started with a special command-line option -
unknown option will abort the server before mysqltest
will start its checks).

mysql-test/suite.pm

@@ -70,12 +70,6 @@ sub skip_combinations {
     unless $::mysqld_variables{'version-ssl-library'} =~ /OpenSSL (\S+)/
        and $1 ge "1.0.1";
 
-  $skip{'include/have_example_key_management_plugin.inc'} = 'no example_key_management_plugin'
-    unless $ENV{EXAMPLE_KEY_MANAGEMENT_PLUGIN_SO};
-
-  $skip{'include/have_file_key_management_plugin.inc'} = 'no file_key_management_plugin'
-    unless $ENV{FILE_KEY_MANAGEMENT_PLUGIN_SO};
-
   %skip;
 }