run: use all available host cpu features for maximum performance

scripts/run.sh

 qemu-system-x86_64 \
 	-vnc :1 \
 	-enable-kvm \
+	-cpu host,+x2apic \
 	-m 1G \
 	-chardev stdio,mux=on,id=stdio \
 	-mon chardev=stdio,mode=readline,default \