[pdftex] Including \pdfsuppressptexinfo in stable branch

[Karl Berry]

    https://mailman.ntg.nl/pipermail/ntg-pdftex/2007-August/003171.html

Sounds fine to me, but sarovar is dead.  Thanh, can you get Heiko's
patch from what was
http://sarovar.org/tracker/?func=detail&atid=495&aid=846&group_id=106
perhaps?  (Or, Heiko, if you read this and have the patch at hand, could
you just send it to me?)

By the way, in the area of reproducible builds, Thanh already installed
some changes from Debian to use a constant time in the output
(look around SOURCE_DATE_EPOCH).  I realize that's only a subset of what
\pdfsuppressptexinfo was doing, but FYI anyway.

Best,
Karl