remove unused variable in test

Author: dfreedm

test/unit/styling-scoped-nopatch.html

@@ -158,7 +158,6 @@
         el = fixture('deep');
       });
       test('scopeSubtree does not modify other elements\' trees', function() {
-        const target = el.$.target;
         const container = el.$.container;
         const deepContainer = el.$.other.$.container;
         const deep = document.createElement('div');