[tlbuild] dvipdfmx rebuild

[Karl Berry]

Hi everyone - ok, let's rebuild dvipdfmx, since the fixes are pretty
significant. I hope this will be the end of the binary updates.

In this particular case, it should be fine to rebuild from the trunk
sources -- as long as *only* dvipdfmx and xdvipdfmx are committed (for
those of you who commit your own binaries). There have been plenty of
other unrelated changes in the trunk, but they won't unduly affect
dvipdfmx. Just don't commit everything else!

Or, if you prefer to compile from branch2019, I've double-released the
dvipdfmx (and previous dvips) changes there, and nothing else.
As in:
  mkdir tlbranch
  cd tlbranch
  svn co -1 svn://tug.org/texlive/branches/branch2019/Build/source .

Thanks,
Karl