Fixed unit tests.

t/perimeters.t

@@ -51,7 +51,7 @@ use Slic3r::Test;
             ($fill_surfaces = Slic3r::Surface::Collection->new),
         );
         $g->config->apply_dynamic($config);
-        $g->process;
+        $g->process_classic;
         
         is scalar(@$loops),
             scalar(@$expolygons), 'expected number of collections';

xs/xsp/PerimeterGenerator.xsp

@@ -36,5 +36,5 @@
     Ref<StaticPrintConfig> config()
         %code{% RETVAL = THIS->config; %};
     
-    void process();
+    void process_classic();
 };