lkdtm/fortify: Consolidate FORTIFY_SOURCE tests

The FORTIFY_SOURCE tests were split between bugs.c and fortify.c. Move
tests into fortify.c, standardize their naming, add CONFIG hints, and
add them to the lkdtm selftests.

Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210818174855.2307828-3-keescook@chromium.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>