How can we configure the Streaming Replication(master-slave) on single SAN storage in PostgreSQL?
I try to answer below, but:

DON'T DO THIS!  

You are planning a disaster recovery setup, but when the disaster hits the shared storage (the SAN), you will stand there with no usable database.

You can do that, yes, just as @a_horse_with_no_name describes in his comment.  You have to have two separate data directories for it, the master pointing to one and the slave to the other.  Setting up the replication is the same as with completely separated machines.

Also, plan regularly taking and testing backups as part of your disaster recovery process.