selftests/exec: load_address: conform test to TAP format output

Conform the layout, informational and status messages to TAP. No
functional change is intended other than the layout of output messages.

Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Link: https://lore.kernel.org/r/20240304155928.1818928-2-usama.anjum@collabora.com


Signed-off-by: Kees Cook <keescook@chromium.org>