leaking_addresses: Use File::Temp for /tmp files

Instead of using a statically named path in /tmp, use File::Temp to create
(and remove) the temporary file used for parsing /proc/config.gz.

Reviewed-by: Tycho Andersen <tandersen@netflix.com>
Link: https://lore.kernel.org/r/20240222220053.1475824-2-keescook@chromium.org


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