Because jar_maker is not in the libs tier, we also rename the libs-%
targets for l10n repacks to l10n-%, which make it clearer what they are
for.
And because multilocale.txt is both a GeneratedFile and a file that is
generated (and installed) via manual build rules, keeping it in the misc
target actually breaks building in toolkit/locales during l10n repacks,
so move it to libs for now.
Differential Revision: https://phabricator.services.mozilla.com/D81766
