test: exclude no_interleaved_stdio test for AIX

pseudo-tty/no_interleaved_stdio has hung a few times
in the last couple of days on AIX.  We believe
it is not a Node.js issue but an issue with python
on AIX. Its being investigated under:
https://github.com/nodejs/node/issues/7973.
Excluding this additional test until we can
resolve the python issue.

Fixes https://github.com/nodejs/node/issues/9765
PR-URL: https://github.com/nodejs/node/pull/9772


Reviewed-By: Sam Roberts <sam@strongloop.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>