KVM: arm64: selftest: Don't try to disable AArch64 support

Trying to cut the branch you are sat on is pretty dumb. And so is
trying to disable the instruction set you are executing on.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
Link: https://lore.kernel.org/r/20250429114117.3618800-3-maz@kernel.org


Signed-off-by: Oliver Upton <oliver.upton@linux.dev>