SERVER-11776 Replication 'isself' check should allow mapped ports

    'isself' should match the ports only if the hosts are being string matched.
    In cases where an instance is being addressed through a proxy port,
    port matching is an incorrect check - it invalidates a genuine match.

Signed-off-by: Benety Goh <benety@mongodb.com>
SERVER-11776 added scott's replication test for the isself command with mapped ports
SERVER-11776 move port check outside loop