Regression in emacs27: synctex forward doesn't scroll anymore

[antoine-levitt]

This works in emacs26 but not in emacs27. When using auctex to correlate pdfs with synctex, the pdf doesn't scroll to the appropriate place when zoomed in and the relevant portion of the page is not visible. I did some exploration and it looks like the offending piece of code is in pdf-util-tooltip-arrow where the vscroll is not appropriately computed or used. I see pdf-view-have-image-mode-pixel-vscroll is true for emacs27, so that might be related?

CC @tylerware who has changed things in a similar area recently and might have an idea...

[antoine-levitt]

Closing in favor of #604