Now that XPT files are not loaded from files at runtime, code for
packaging XPT files can be removed.
This means that a couple of test XPIDL interfaces will get shipped in
builds to users that weren't before, but I don't think that matters
much.
This also puts XPT files into the local objdir for the XPIDL makefile,
instead of dist/bin, because they are no longer part of the
distribution.
MozReview-Commit-ID: 7gWj8KWUun3
--HG--
extra : rebase_source : 65bac47c2cd1a20b3c675a01b44a25a1d2d3ab7a
e80864c94c