msc: TC_ho_inter_bsc: wait for the target BSC to become ready
A race condition may occur between the two testcase components emulating BSCs: the source BSC initiates handover to the terget BSC before the later completes connection establishment with the MSC. In this case, the MSC fails to find the target peer and rejects our HandoverRequired with HandoverRequiredReject.
Target RAN peer from neighbor config is not connected: Cell ID CGI:023-42-5-6 resolves to target address 0.24.2 Cannot find target peer for cell ID CGI:023-42-5-6 Attempted Handover to 1 cells without success
Let's avoid this by waiting for the target BSC to become available before initiating the handover procedure. Use the COORD port ("intercom") to signal readiness of the target BSC.
