This was done so it would work when circular buffer holds other things
that are not unique_pointers. Queue and pop_func had to be made public
to be able to call the pop_func when an SDU is discarded.
* Added ability to discard to dyn_block_queue
* Change way of keeping track of SDUs
* Check nullptr in poping callback. Starting to check for nullptr in RLC read_pdu.
* Adding RLC discard tests
* Clearing PDCP info when RLC discard happens
* Read SDUs until they are no longer nullptr
* Changed discard_if to use template argument
Andre Puschmann
Pedro Alvarez
Francisco
Codebot