Meta: Force legacy xAPIC when using 8 cores or less

This is merely so that we exercise the legacy xAPIC code when we don't
really need x2APIC.

Meta/run.sh

@@ -124,6 +124,10 @@ fi
 
 [ -z "$SERENITY_QEMU_CPU" ] && SERENITY_QEMU_CPU="max"
 [ -z "$SERENITY_CPUS" ] && SERENITY_CPUS="2"
+if [ "$SERENITY_CPUS" -le 8 ]; then
+    # Explicitly disable x2APIC so we can test it more easily
+    SERENITY_QEMU_CPU="$SERENITY_QEMU_CPU,-x2apic"
+fi
 
 if [ "$SERENITY_ARCH" != "aarch64" ]; then
     if [ -z "$SERENITY_SPICE" ] && "${SERENITY_QEMU_BIN}" -chardev help | grep -iq qemu-vdagent; then