Avoid explicit MC unpacker scheduling
Explicitly scheduling the unpacking can cause conflicts with other
such schedulings (e.g. if it's done in Moore). With implicit scheduling
we can let the HLTControlFlowMgr
take care of the data-flow dependencies,
rather than trying to satisfy them by hand via the control flow.
The test failures in MooreAnalysis introduced by Moore!601 (merged) motivated this MR.