fix: usr: Add a compatibility shim for older libuv versions (< 1.19.0)

The uv_stream_get_write_queue_size() is supported only in relatively newer versions of libuv (1.19.0 or higher).  Provide a compatibility shim for this function , so BIND 9 can be built in environments with older libuv version.

Fixes: #4822
Merge branch 'uv_stream_get_write_queue_size_wrapper' into 'bind-9.18'

See merge request isc-projects/bind9!9153