* dbus/dbus-test-main.c (main): Take optional specific test
	argument.

	* dbus/dbus-test.c (run_test): New function, runs a test function
	with no data directory.
	(run_data_test): Like above, but takes data directory.
	(dbus_internal_do_not_use_run_tests): Take
	specific test argument.  Replace lots of cut n' paste code
	with run_test and run_data_test.

	* dbus/dbus-test.h: Update prototype for
	dbus_internal_do_not_use_run_tests.