* tests/openpgp/run-tests.scm (test::run-sync): Pass additional
arguments to the test.
(test::run-sync-quiet): Likewise.
(test::run-async): Likewise.
(run-tests-{parallel,sequential}-isolated): Create a tarball of the
gnupghome, then extract it for each test.
* tests/openpgp/setup.scm: Refactor into functions, add an interface
to tar-up the created environment, and untar it multiple times.
Signed-off-by: Justus Winter <justus@g10code.com>