test: execute g_test_run when tests are skipped

test: execute g_test_run when tests are skipped

Sometimes a test's main() function recognizes that the environment
does not support the test, and therefore exits.  In this case, we
still should run g_test_run() so that a TAP harness will print the
test plan ("1..0") and the test will be marked as skipped.

Signed-off-by: Paolo Bonzini <[email protected]>
Message-Id: <1543513531[email protected]>
Reviewed-by: Eric Blake <[email protected]>
Reviewed-by: Thomas Huth <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>