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.

.github/workflows/mkosi.yml

@@ -123,6 +123,7 @@ jobs:
         ToolsTreeDistribution=fedora
         # TODO: Drop once https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2038777 is fixed in Github Actions
         QemuFirmware=uefi
+        QemuMem=4G
         # We build with debuginfo so there's no point in mounting the sources into the machine.
         RuntimeBuildSources=no
         EOF