[PATCH 0/4] MR9348: comctl32/imagelist: Pre-multiply rgb by the alpha channel in add_dib_bits for v6.

[Ziqing Hui (＠zhui)]

We used to do this when drawing the image. But our tests show that for v6,
the image bitmaps have been alpha pre-multiplied before drawing.
So we should do this when adding images.