[tlbuild] Building trunk

[Karl Berry]

    This is not perfect, but is it that complicated to provide a small
    chunk of TL tree in order to use TL2010 binaries (e.g. latex, pdftex)

Yes, it is complicated (especially to maintain over time).  I am
certainly not to copy all of latex into the source hier just to run a
tiny test.  IMHO, all tests should be able to be run with -ini, so
formats do not need to be built.

I'll see what can be done about the dvipng test.  (We already simplified
it considerably.)

Thanks,
k