Allow testnet creation with no validator nodes (#3846)

net/gce.sh

@@ -322,6 +322,7 @@ EOF
     cloud_ForEachInstance waitForStartupComplete
   fi
 
+  if [[ $additionalFullNodeCount -gt 0 ]]; then
     echo "Looking for additional fullnode instances..."
     for zone in "${zones[@]}"; do
       cloud_FindInstances "$prefix-$zone-fullnode"
@@ -332,6 +333,7 @@ EOF
       cloud_ForEachInstance recordInstanceIp fullnodeIpList
       cloud_ForEachInstance waitForStartupComplete
     done
+  fi
 
   if $externalNodes; then
     echo "Let's not reset the current client configuration"
@@ -510,6 +512,7 @@ EOF
       "$startupScript" "$bootstrapLeaderAddress" "$bootDiskType"
   fi
 
+  if [[ $additionalFullNodeCount -gt 0 ]]; then
     num_zones=${#zones[@]}
     numNodesPerZone=$((additionalFullNodeCount / num_zones))
     numLeftOverNodes=$((additionalFullNodeCount % num_zones))
@@ -524,6 +527,7 @@ EOF
     done
 
     wait
+  fi
 
   if [[ $clientNodeCount -gt 0 ]]; then
     cloud_CreateInstances "$prefix" "$prefix-client" "$clientNodeCount" \