test: allow sanitized binaries to dump a core

test: allow sanitized binaries to dump a core

If a binary built with ASan crashes for a reason unrelated to ASan
stuff, we're left with pretty much nothing, as there is neither an ASan
trace nor a coredump. Let's make this slightly more debug-able by
allowing such binaries to dump a core, but without the huge shadow map
(we should be actually fine by just setting disable_coredump=0, since
use_madv_dontdump defaults to true, but let's play it safe and not
potentially dump a 16+ TB core file).