MFC r346431,r347417,r348019:

MFC r346431,r347417,r348019:

r346431 (by lwhsu):

Specify using Python2, these .py files have not been converted to use Python3
yet, but the default Python version in ports has been switched to 3.

r347417:

Refactor tests/sys/opencrypto/runtests

* Convert from plain to TAP for slightly improved introspection when skipping
  the tests due to requirements not being met.
* Test for the net/py-dpkt (origin) package being required when running the
  tests, instead of relying on a copy of the dpkt.py module from 2014. This
  enables the tests to work with py3. Subsequently, remove
  `tests/sys/opencrypto/dpkt.py(c)?` via `make delete-old`.
* Parameterize out `python2` as `$PYTHON`.

PR:		237403

r348019:

Allow the end-user to pass along arguments to cryptotest.py via `$CRYPTOTEST_ARGS`

This allows someone to use `-v` to dump out standard output.