umvu: add partial arm64 support

[fish4terrisa-MSDSM]

Added partial arm64 support. Now at least bash, vuname and other normal apps worked.

umvu -l 7 -s 7 -S busybox ash
Purelibc found: nested virtualization enabled
~ $ vuname -a
Linux ArchLinux-ACE3-Keqing 5.15.123-Fish4terrisa-MSDSM+ #1 SMP PREEMPT Mon Apr 28 18:14:32 UTC 2025 aarch64 GNU/Linux/VUOS 1243241

VUOS modules arent working:

umvu -l 7 -s 7 -S busybox ash
Purelibc found: nested virtualization enabled
~ $ vu_insmod vudev
vudev: Invalid argument

and I really cannot figure out why. Also I have to set disable_seccomp_optimization(-S), otherwise I'll get:

umvu -l 7 -s 7 true
Purelibc found: nested virtualization enabled
munmap_chunk(): invalid pointer

I know nearly nothing about ptrace and vuos, so probably it contains bugs and implemention errors.
Hope this may help vuos start to support arm64 :)