The XML output for other tables is also sorted alphabetically
by glyph name, not by glyph order.
This reverts commit c77e9fe12d5879aeb79c05f8ececebb3275524b7.
Before this change, the AAT lookups were alphabetically sorted by glyph name,
but it seems more natural to write XML in the usual glyph order. No changes to
the binary format (which already was in glyph order); this only affects how
XML output is produced.