Fix: inconsistent block stat by JVET-AD0222 when virtual boundary is enabled

JVET-AD0222 gathers block statistics from residuals of CTU. If a CTU is segmented by a virtual boundary, the residual data is transferred to an temporary buffer for statistics collection. However, residuals in temporary buffer starts from (0,0) while absolute coordinate is passed to collect statistics which resulting in inconsistent outcomes. The fix is using relative coordinates to fetch residuals from correct position.