Don't add binding to function twice when var binding shares with fu…

…nction param [fix]

lib/instrument/visitors/assignee.js

@@ -194,9 +194,8 @@ function IdentifierVar(node, state) {
 			binding.isVar = true;
 		} else {
 			binding = createBinding(block, varName, {isVar: true}, state);
+			if (fn) fn.bindings.push(binding);
 		}
-
-		if (fn) fn.bindings.push(binding);
 	} else if (binding.isFrozenName) {
 		return;
 	}