lib/test_meminit: use && for bools

lib/test_meminit: use && for bools

As pointed out by Dan Carpenter, test_kmemcache() was using a bitwise AND
on two bools instead of a boolean AND.  Fix this for the sake of code
cleanliness.

Link: https://lore.kernel.org/20260504100637.1535762-1-glider@google.com
Fixes: 5015a300a522 ("lib: introduce test_meminit module")
Signed-off-by: Alexander Potapenko <glider@google.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Closes: https://lore.kernel.org/kernel-janitors/afOcIan1ap9kD26M@stanley.mountain/
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>