add pattern rest parameters test

test/fixtures/transformation/es6-parameters.rest/pattern/actual.js

@@ -0,0 +1,3 @@
+var foo = function (...[a, b]) {
+
+};

test/fixtures/transformation/es6-parameters.rest/pattern/expected.js

@@ -0,0 +1,14 @@
+"use strict";
+
+var _slicedToArray = function (arr, i) { if (Array.isArray(arr)) { return arr; } else { var _arr = []; for (var _iterator = arr[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) { _arr.push(_step.value); if (i && _arr.length === i) break; } return _arr; } };
+
+var foo = function () {
+  for (var _len = arguments.length, _ref = Array(_len), _key = 0; _key < _len; _key++) {
+    _ref[_key] = arguments[_key];
+  }
+
+  var _ref2 = _slicedToArray(_ref, 2);
+
+  var a = _ref2[0];
+  var b = _ref2[1];
+};