With the new pikepdf 1.2.0 we no longer need to hold file handles
open because of the "copy to memory" functionality. We retain
the behavior of closing/reopening the output PDF every 100 pages as
a way to limit memory usage.
If using --tesseract-timeout 0 and any image processing on a file with
more than 100 pages, the weave handoff will occur. Ensure this
works correctly even if no Glyphless font is present.
Closes#347