Reduce number of tiles for big images with openGL

Every call to glDrawArrays exchanges data between CPU
and GPU, keeping the number low allows for big images to render quickly. This is important on systems that drop stylus events to
prevent jagged lines.

The calulation keeps the tile size to a minimum of 1, this is ok on most
cases. Also we avoid using the MAX_TEXTURE_SIZE, as it also
provkes some slowdown issues.

BUG:414025