i3test::XTEST: don’t “use i3test” to avoid clobbering state

Before this commit, the $i3_autostart variable was accidentally overridden.

testcases/lib/i3test/XTEST.pm

@@ -5,7 +5,8 @@ use strict;
 use warnings;
 use v5.10;
 
-use i3test i3_autostart => 0;
+use Test::More;
+use i3test::Util qw(get_socket_path);
 use lib qw(@abs_top_srcdir@/AnyEvent-I3/blib/lib);
 use AnyEvent::I3;
 use ExtUtils::PkgConfig;