The tests have inadvertent dependencies on each other so let's avoid
those by changing to a system that returns a null-terminated list of
test functions and our test runner iterates over those and forks off one
process per function.
Part of refactoring the tests into a single binary,
to make partial rebuild slightly faster and less verbose.
Prepares for joining test/xi2/protocol-* into a single binary.
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Mihail Konev <k.mvc@ya.ru>