Fix problems with ssh timeout in ptest CI job

There are several known problems with slirp, so let's try and see if we can stabilize our CI by using tap networking in ptest job, just as we already do in acts job.

conf/distro/oniro-openharmony-linux.conf

@@ -40,6 +40,9 @@ INHERIT += "uninative"
 # instead.
 HOSTTOOLS += "ip ping ps scp ssh stty"
 
+# Yocto does not have ssh-keygen-native, so we need to use ssh-keygen from host
+HOSTTOOLS += "ssh-keygen"
+
 # Default to enabling serial debug console on RaspberryPi
 # Placed here to amend the machine config living in meta-raspberrypi
 ENABLE_UART:raspberrypi4-64 ?= "1"