This reverts commit 945566ff43.
As discussed on the mailing lists and with Humdinger off-list:
* The general design concensus tends slightly towards DejaVu, as metrics
of DejaVu look much better (DejaVu 12 and Noto 13 are roughly the same size,
but Noto has much wider margins with that)
* While Noto does have a wider set of fonts with support for lots of
different languages, DejaVu actually has built-in support for more
Unicode languages (the default Noto has, as far as I can tell, only
Latin/Greek/Cyrillic [2416 glyphs], while DejaVu also has Armenian, Georgian,
and a few other scripts too [5119 glyphs].)
* The worse rendering of DejaVu appears to have been somewhat rectified by
disabling the average-based subpixel filter in app_server.
