This allows using one single wineprefix, one wineserver and one single wine executable for running both arm and arm64 executables.
This setup actually has worked earlier; Ubuntu 22.04 packages Wine 6.0, where the wine32 + wine64 packages together end up working this way. However, since Wine 6.0, a couple of refactorings has broken this setup along the way; reinstate this way of working.
The new wow64 mode probably won't work on arm, as it's not easily possible to switch between 32 and 64 bit execution mode within a process, as far as I know, but the old wow64 mode is still a great convenience - especially considering distro-packaged use for users who aren't familiar with the particular quirks on this architecture.
-- v2: configure: Allow using --enable-win64 on aarch64 server: Include ARMNT as one of the supported architectures on aarch64 ntdll: Allow running arm/aarch64 in (old) wow64 mode