These previously relied on embedding test-specific code in libdbus,
but they actually only need public APIs, private interfaces that get
exported anyway for the benefit of dbus-daemon, and the TAP helpers;
so we can run them even in production builds.
Signed-off-by: Simon McVittie <smcv@collabora.com>
Instead of exposing _dbus_sha_test() as a private exported symbol,
we can expose _dbus_sha_compute(), which is the only thing called by
the test that isn't already exported.
Signed-off-by: Simon McVittie <smcv@collabora.com>