[Encode] Fix AV1 temporal MV buffer and SavedOrderHints for deduplicated refs

When ConsolidateRefFlag() deduplicates references pointing to the same
frame, m_refFrameFlags only keeps one bit per unique frame. This caused
two issues in AVP programming:
1. AVP_PIPE_BUF_ADDR_STATE: temporal MV buffer slots for refs in
   m_activeRefBitmaskMfProj but not m_refFrameFlags were left to
   concealment, diverging from VDENC which uses the correct bitmask.
2. PopulateReferenceFramePOCs(): savedOrderHints rows were only populated
   for refs in m_refFrameFlags, leaving deduplicated ref rows all-zero.
   This broke motion field projection (AV1 spec 7.9.1) which reads
   savedOrderHints for all refs in the projection set.
Fix: (1) Add a supplementary loop in AVP_PIPE_BUF_ADDR_STATE to fill
temporal MV gaps using m_activeRefBitmaskMfProj. (2) Remove the
m_refFrameFlags guard from PopulateReferenceFramePOCs() so all valid
reference types get their savedOrderHints populated. Both paths add
validation guards (index bounds, invalid picture, null pointer) before
dereferencing reference frame entries. Update unit test expected data
to reflect the new validation behavior.