mkosi: Sanitizer improvements

mkosi: Sanitizer improvements

- Let's set the environment on the kernel command line so it applies
to initrd and main system.
- Let's add the necessary wrappers that are also added in test-functions.
Unlike test-functions we don't use gcc/clang to get the library path as
that requires installing gcc/clang in the initrd.
- Let's drop the hack to get journald writing to the console and have
it write to kmsg instead. We'll get the output either way.
- Stop removing libstdc++ and sanitizer libraries from Arch Linux
initrds and other images as it's required by the sanitizer libraries.
- Add a workaround for specifying extra meson options for opensuse
- Add a leak sanitizer suppression file as a workaround for a false
positive leak in verify_selinuxmnt() in libselinux. We do a soname match
because the stacktrace can't be properly symbolized on Debian.