Part of page not rendered if group bounding box is placed outside the canvas

[Snuffleupagus]

After #3798 was merged (checked with git bisect), the following files no longer renders completely:

• http://particuliers.lcl.fr/quotidien/cartes/simplifier_quotidien/carte-visa-cleo/Ressources/pdf/dispositions_generales_cb_cleo.pdf#page=2
• http://www.vrr.de/imperia/md/content/fahrten/stadtlinienplaene/wuppertal_2012.pdf

The relevant error message from the console:

InvalidStateError: An attempt was made to use an object that is not, or is no longer, usable

It turns out that the issue in these files is that some of the bounding boxes are placed entirely outside of the canvas, causing bounds to be undefined since the two regions don't intersect: https://github.com/mozilla/pdf.js/blob/master/src/display/canvas.js#L1510.
An example of the issue (taken from the first file): The bounding box is [798.569357132554, 117.22800148665908, 1031.8493640848396, 267.46800596415994], but the canvas dimensions are [0, 0, 755, 793].