systemd: Fix and expand ptests

systemd: Fix and expand ptests

systemd-ptest only runs a couple of tests currently.
* Install all test binaries and required data files
* Add missing runtime dependencies for -ptest
* Fix paths required for on-target testing in do_configure_prepend()
* cleanup do_install_ptest()

For reference, results on current core-image-sato:
  PASS: 109
  SKIP:   5
  FAIL:   2

test-execute failure:
https://github.com/systemd/systemd/issues/2852

test-acl-util failure:
https://bugzilla.yoctoproject.org/show_bug.cgi?id=9269

Fixes [YOCTO #8767].

Signed-off-by: Jussi Kukkonen <jussi.kukkonen@intel.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>