PT-2264 - pt-query-digest Pipeline process 11 (--output slowlog) caused an error: Wide character

- Skipped test for versions before 8.0

t/pt-query-digest/pt-2264.t

@@ -17,6 +17,11 @@ use Sandbox;
 
 my $dp = new DSNParser(opts=>$dsn_opts);
 my $sb = new Sandbox(basedir => '/tmp', DSNParser => $dp);
+
+if ( $sandbox_version lt '8.0') {
+   plan skip_all => "Requires MySQL 8.0 or newer";
+}
+
 my $dbh = $sb->get_dbh_for('master');
 
 if ( !$dbh ) {