(g2-UU+9909): Unify g2-HD-FT2691 instead of G-HD-FT2691.

(g2-UU+9909): Unify g2-HD-FT2691 instead of G-HD-FT2691.
(o-UU+990C): Unify o-J83-3142, J90-3142 and JX1-3142.
(G-JX2-7C55): Unify o-UU+4B3B and o-JX2-7C55 instead of G-UU+4B3B,
G-JX2-7C55 and G-HD-JD9253.
(g2-JX2-7C55): Unify g2-HD-JD9253 and G-UU+4B3B.
(K0-4E3D): Unify U+FA2C and KU+9928.
(U+994D): Use `->denotational' instead of `->subsumptive'.
(G-UU+994E): Unify o-UU+994E instead of UU+994E.
(o-J2004U+9957): Unify o-JX3-3642.