Comment 2 for bug 1330379

Adjust prefetching in trunk revision 1582 to allow prefetching of as many tiles as we would prefetch pages without tiling enabled. (With forward prefetching being issued before any backward prefetching if it is constrained by the tile budget.)

Maybe the one-tile-one-page ratio should be enlarged a bit, e.g. allowing to request rendering of twice as many tiles as pages? Unity however seems to work as intended.