- To check the current slot is the scheduled slot(UL slot - K2) and
  only execute the post processor in scheduled slot.

This commit enables more slots so that the "real UE" preprocessor can
schedule them. The DL phytest preprocessor continues to only schedule
slots 1 & 3.  This is because the OAI-UE needs to have PUCCH scheduled
at least six slots in advance.  Since we do not support this (yet), but
assume that two slots are enough, we schedule the UE only in slot 1 & 3
so it has 6 slots until slot 7 to send PUCCH.

made L1 DLSCH encoding stateless. harq_pid/round information are not kept in PHY. Full channel encoding is performed for each transmission of a transport block.
Still to be done: test, then cleanup data structures and fix unitary simulations.