I used GCP compute node with HTTP/HTTPS enabled. I have tested the GC compute instances out before and know they at least deliver HTTP stuff from apache.
Note that enabling the HTTP/HTTPS will unlock only 80 and 443 ports. You should configure the firewall of your gCloud instance to allow the traffic on 8080.
Also, a way to test the XWiki instance is to connect via ssh to your VM instance and execute a ping/wget on localhost:8080.