skip flow types when finding rest parameter references

test/core/fixtures/transformation/es6.parameters/rest-flow-parameter-reference/actual.js

@@ -0,0 +1,9 @@
+function foo(
+  x: Object,
+  ...types
+): { types: Array<number>, x: Object } {
+  return {
+    types: types,
+    x: x,
+  };
+}

test/core/fixtures/transformation/es6.parameters/rest-flow-parameter-reference/expected.js

@@ -0,0 +1,12 @@
+"use strict";
+
+function foo(x) {
+  for (var _len = arguments.length, types = Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {
+    types[_key - 1] = arguments[_key];
+  }
+
+  return {
+    types: types,
+    x: x
+  };
+}