native Promise broken in node 10.0 and 10.1

in node < 10, or 10.2+, the following code in the REPL shows a rejected promise. in node 10.0 and 10.1, however, the promise is forever pending.
```js
var r, p = new Promise(y => { r = y; }); r({ then() { throw 42; } }); p;
```