tests: disable coredumps on sanity-test

SEGV and ABRT by default cause a core dump, which may create a file,
launch crash handlers, and so on. sanity-test has 21 processes that
are expected to crash like this. Disable core dumps on them all.

I counted 21 entries in coredumpctl list, while only 16 functions needed
patching. After this patch no entries appear in coredumpctl list.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Daniel Stone <daniels@collabora.com>