ignore this and arguments when performing TCO on shadowed functions - fixes #1564

test/core/fixtures/transformation/es6.tail-call/shadow/actual.js

@@ -0,0 +1,8 @@
+(function(){
+  var foo = () => {
+    this;
+    arguments;
+    foo();
+  };
+  foo();
+});

test/core/fixtures/transformation/es6.tail-call/shadow/expected.js

@@ -0,0 +1,13 @@
+"use strict";
+
+(function () {
+  var _this = this,
+      _arguments = arguments;
+
+  var foo = function foo() {
+    _this;
+    _arguments;
+    foo();
+  };
+  foo();
+});