Improve x86_64 emulation on arm64 platform

[gayanper]

The current x86_64 emulation try to use the apple-hypervisor as the accelerator which only use 1 cpu on the host machine regardless how much cpu core are assigned.

But changing the accelerator parameter from apple hypervisor to tcg with few more extra parameters which UTM use when emulating improved the emulation performance up to the point docker qemu userspace emulation.

[jandubois]

changing the accelerator parameter from apple hypervisor to tcg with few more extra parameters which UTM use

I was about to ask what the "few more extra parameters" are, but it looks like you are working on a PR for this already, so I'll wait until you open that for review! :)

[AkihiroSuda]

@gayanper Do you plan to submit a PR?

[gayanper]

Yes i will provide a PR with the suggested changes during today.