[9.20] fix: usr: Fix long-running incoming transfers
requested to merge backport-4949-fix-ignored-and-invalid-dispatch-timeout-in-dns_xfrin-9.20 into bind-9.20
Incoming transfers that took longer than 30 seconds would stop reading from the TCP stream and the incoming transfer would be indefinitely stuck causing BIND 9 to hang during shutdown.
This has been fixed and the max-transfer-time-in and max-transfer-idle-in timeouts are now honoured.
Closes #4949 (closed)
Backport of MR !9531 (merged)