Detect native arch dynamically

[zacksiri]

Currently from what I read from the setup script. It seems anything which is not x86 will setup qemu. However in the use case where we're using a self hosted runner that the host is natively aarch64 it should not setup qemu.

[zacksiri]

If you can give me pointers I can probably handle this and submit a PR.

Update:

After some research can't we use uname -m to detect the architecture? If the argument passed in doesn't match we provision qemu.