When CTU size is 256, BVP for IBC AMVP list exceed the max IBC search range.

In ECM-8.0, the max IBC search range is 2x128 rows. (1 CTU row when CTU size is 256. 2 CTU rows when CTU size is 128.) And two BVP candidate are derived for IBC AMVP list The AMVP BVP0 is set to the nearest valid location to the current block (-cbWidth or -cbHeight). The AMVP BVP1 is set to the farthest position from the current block in the valid reference region (-pu.Y().x or -pu.Y().y).

In below source code, when CTU size is 256, AMVP BVP1(pInfo->mvCand[1]) exceed the max IBC search range.

    const int ctbSize     = pu.cs->sps->getCTUSize();
    const int numCurrCtuY = (pu.Y().y >> (floorLog2(ctbSize)));
    const int rrTop       = (numCurrCtuY < 3) ? -pu.Y().y : -((pu.Y().y & (ctbSize - 1)) + 2 * ctbSize);
    pInfo->mvCand[0] = Mv(0,std::max(-static_cast<int>(pu.lheight()), rrTop));
    pInfo->mvCand[0].changePrecision(MV_PRECISION_INT, MV_PRECISION_INTERNAL);
    pInfo->mvCand[1] = Mv(0,rrTop);
    pInfo->mvCand[1].changePrecision(MV_PRECISION_INT, MV_PRECISION_INTERNAL);