test: add test for piping large input from stdin

Check that piping a large chunk of data from `process.stdin`
into `process.stdout` does not lose any data by verifying that
the output has the same size as the input.

This is a regression test for #5927 and fails for the commits
in the range [ace10094..89abe868).

PR-URL: https://github.com/nodejs/node/pull/5949


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>