Add checks for `stream_pipe.cc`

[wooffie]

I think we should add check for nullptr here:

node/src/stream_pipe.cc

Line 280 in b4280ef

StreamBase* sink = StreamBase::FromObject(args[1].As<Object>());

We checked that args is Object, but not checked for type after converting

I'll prepare PR

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Reporter: Burkov Egor (eburkov@rvision.ru).

Organization: R-Vision (support@rvision.ru).