by emulating it with SmFontNode.
In case of <mo>, current implementation supports only the one named
with an alphabet.

Change-Id: I827a7e80f5aa94e243098a6e50eb758cf915c282
Reviewed-on: https://gerrit.libreoffice.org/31240Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Takeshi Abe <tabe@fixedpoint.jp>