Improve support for MSVC ARM64

[scribam]

This does not allow to build Unicorn with MSVC ARM64 as this seems unsupported by qemu currently but it fixes few errors found in CMakelists.txt.
Using only CMAKE_SIZEOF_VOID_P EQUAL 8 is not enough to detect x86_64 anymore as ARM64 returns the same value

[wtdcode]

Even you make the compiler right, currently it is not possible to really run unicorn on windows arm64 natively as we have inline assembly. I was working on this but lack machines to test.

[wtdcode]

See the blockers here: https://github.com/unicorn-engine/unicorn/blob/master/qemu/accel/tcg/translate-all.c#L930

Another workaround is that we allocate static translation buffers as qemu does on arm64.

[scribam]

There is a runner available on GitHub Actions: windows-11-arm (https://github.blog/changelog/2025-08-07-arm64-hosted-runners-for-public-repositories-are-now-generally-available/)

Clearly not the best solution for development but maybe enough for tests.

I don't plan to look at the assembly as it is beyond my skills so feel free to close this PR if you think it does not bring anything useful for now

[wtdcode]

Thanks for letting me know and I will leave this PR open for furture arm64 support work.