check: add a flag for direct printing of test output

check: add a flag for direct printing of test output

Add -d debug dump flag to ./check to directly print a test output
to stdout, instead of just saving it into a file and showing a diff
snippet.

Useful e.g. when writing a new test.

Signed-off-by: Jan Tulak <jtulak@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>