Fixed a perl test that was mistkanely adjusted after ClipperLib refactoring.

t/perimeters.t

@@ -394,7 +394,7 @@ use Slic3r::Test;
         });
         return scalar keys %z_with_bridges;
     };
-    ok $test->(Slic3r::Test::init_print('V', config => $config)) == 2,
+    ok $test->(Slic3r::Test::init_print('V', config => $config)) == 1,
         'no overhangs printed with bridge speed';  # except for the two internal solid layers above void
     ok $test->(Slic3r::Test::init_print('V', config => $config, scale_xyz => [3,1,1])) > 2,
         'overhangs printed with bridge speed';