MLBEDSW-2434: optim: 19_12_32, bilinear + depthwise int8 output diff

This commit fixes a bug where there would be an off-by-one error
in some cases for ResizeBilinear.

It is resolved by treating it the same way as an AvgPool in
regards to setting the zero point.

Signed-off-by: Dwight Lidman <dwight.lidman@arm.com>
Change-Id: I2835d5dcf360f65e19265c339e5ffd02de16c823