Fix/3.x/issue 3200

I could only reproduce this issue by running same tests at same time in different processes. I don't know how was this possible in our CI environment. 

To solve this issue, I check available ports for tests. "port-auto-increment" is not suitable for these test cases since these ports are also used for client configurations. So I check ports by myself and use these ports in both of instance and client configurations. 
@ahmetmircik nice catch, will fix