(PUP-2999) Use host.tmpdir for agent tmpdirs

PUP-2999 switched these two tests to use Beaker's new
create_tmpdir_for_user() helper, but this has a bug related to windows
acceptance (QENG-1108) in that it doesn't end up prepending a 'cmd.exe
/c' and we get pathing issues with our current acceptance setup on
windows.

Just switching back to using host.tmpdir calls for now; the original
changes were for jvm-puppet, but that is master only, and these are
agent calls.
Merge branch 'issue/master/pup-2999-agent-tmpdirs-on-windows'

* issue/master/pup-2999-agent-tmpdirs-on-windows:
  (PUP-2999) Use host.tmpdir for agent tmpdirs