socket bound on loopback address do not receive packet until netif_poll_all() is called.

In following test if call to netif_poll_all() is removed from line 163 i.e. after sending the UDP packet then receiving socket's event handler is not called.

https://github.com/mazimkhan/sal-test/blob/devel-transport/test/tc_6ib_00000001/main.cpp

Start with test/tc_6ib_00000001/main.cpp in the linked sal-test repository, especially line 163 and the UDP send/receive sequence. Run the test with and without netif_poll_all() and trace why the receiving socket event handler differs; done means the handler is called after sending without that explicit poll.

Written by the indexing model from the issue text.