v8: upgrade to 3.20.17.13

fixes #6235
test: add regression test for #6235
fs: remove duplicate !options case

I haven't actually tested this code, but was reading it due to a
post that linked to the code here:

    http://dailyjs.com/2013/09/26/libuv/

As I was reading through the code, I noticed a path that can't
be reached.

I didn't strictly follow the contributing guide:

    https://github.com/joyent/node/wiki/Contributing

but the change seems safe.

Feel free to close this out. I'm not sure if it was just an oversight
or what.