Any non-zero exit code is grounds for ignoring the 'test --list'
output.
This also causes get_subtests() to return the actual process exit code
rather than a generic internal error when it fails to parse the test
list.
Signed-off-by: Francois Gouget <fgouget@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>