Fix RPR issues

• Ticket 560: Unsafe use of reference picture PPS pointers.
• Ticket 561: Incorrect clipping at picture border and insufficient picture buffer margin.
• Ticket 562: Incorrect calculation of refHeight.
• Ticket 563: Interaction between RPR and BDOF.
• Ticket 568: Disable sub-PU grouping optimization with RPR.
• Ticket 569: Disable clipping of unscaled RPR motion vectors.
• Ticket 571: Fix multiplication overflow in scaled MV position.