ot::Ip6::Tcp::Endpoint::ReceiveContiguify() method

Reorganizes the receive buffer to be entirely contiguous in memory. This is optional; an application can simply traverse the linked buffer chain obtained by calling @p otTcpReceiveByReference. Some applications may wish to call this function to make the receive buffer contiguous to simplify their data processing, but this comes at the expense of CPU time to reorganize the data in the receive buffer. @sa otTcpReceiveContiguify