Meta: Make SERENITY_RUN=ci work with AArch64

This in turn enables `./Meta/serenity.sh test aarch64` and the CI
scripts to work with the AArch64 port.

As the RPi doesn't have a debugcon-like device, we create two serial
devices. The system console, UART0 is redirected to `debug.log`, while
UART1 is made available to the userspace and is used as the stdout for
the test runner script.

We are not yet able to run the full test suite, as the kernel panics due
to some unimplemented features.

Note that Qemu `master` or our patched Qemu build is required for
`SystemServer` to recognize the `system_mode=self-test` parameter.

Meta/run.sh

@@ -513,6 +513,22 @@ elif [ "$SERENITY_RUN" = "limine" ]; then
 elif [ "$SERENITY_RUN" = "ci" ]; then
     # Meta/run.sh ci: qemu in text mode
     echo "Running QEMU in CI"
+    if [ "$SERENITY_ARCH" = "aarch64" ]; then
+      "$SERENITY_QEMU_BIN" \
+            $SERENITY_EXTRA_QEMU_ARGS \
+            $SERENITY_VIRT_TECH_ARG \
+            -M raspi3b \
+            -d guest_errors \
+            -no-reboot \
+            -drive file=${SERENITY_DISK_IMAGE},if=sd,format=raw \
+            -nographic \
+            -monitor none \
+            -display none \
+            -serial file:debug.log \
+            -serial stdio \
+            $SERENITY_KERNEL_AND_INITRD \
+            -append "${SERENITY_KERNEL_CMDLINE}"
+    else
         "$SERENITY_QEMU_BIN" \
             $SERENITY_EXTRA_QEMU_ARGS \
             $SERENITY_VIRT_TECH_ARG \
@@ -528,6 +544,7 @@ elif [ "$SERENITY_RUN" = "ci" ]; then
             -debugcon file:debug.log \
             $SERENITY_KERNEL_AND_INITRD \
             -append "${SERENITY_KERNEL_CMDLINE}"
+    fi
 else
     # Meta/run.sh: qemu with user networking
     "$SERENITY_QEMU_BIN" \