selftests/nolibc: fix EXTRACONFIG variables ordering

The variable block got disordered at some point.

Use the correct ordering.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Link: https://lore.kernel.org/r/20250623-nolibc-sh-v2-1-0f5b4b303025@weissschuh.net