Fix make distcheck

* set util binary paths relative to top_builddir
* set pactest.py path relative to top_srcdir
* include tap.py in check_SCRIPTS

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>
Signed-off-by: Allan McRae <allan@archlinux.org>
TESTS: add missing tests

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>
Signed-off-by: Allan McRae <allan@archlinux.org>