texLiveFull: fix build on Darwin

Added --with-system-icu=no, --with-system-harfbuzz=no (looks like the
omission of --with-system-icu was not sufficient to force the builder
not to look for system ICU libs).

Disable building bibtex-x: complains about missing ICU directory.

Disable building dvisgm: a test fails (and I can't work out how to
prevent the tests from running just for this).