Satisfy test suite and CLI

t/gcode.t

@@ -14,9 +14,8 @@ use Slic3r::Test;
 
 {
     my $gcodegen = Slic3r::GCode->new(
-        config      => Slic3r::Config->new_from_defaults,
-        layer_count => 1,
-        extruders   => [],
+        layer_count     => 1,
+        extruders       => [],
     );
     $gcodegen->set_shift(10, 10);
     is_deeply $gcodegen->last_pos->arrayref, [scale -10, scale -10], 'last_pos is shifted correctly';