Avoid duplicate names in glyphorder table.
Avoid duplicate names in glyphorder table.

When adding a single glyph that was not in the cmap, this was adding the
name for that glyph twice.

googlefonts/noto-emoji,dougfelt/noto-emoji,julroy67/noto-emoji,moyogo/noto-emoji,moyogo/noto-emoji,dougfelt/noto-emoji,googlefonts/noto-emoji,radiocane/noto-emoji,dougfelt/noto-emoji,googlei18n/noto-emoji,googlefonts/noto-emoji,mxalbert1996/emojione-android,julroy67/noto-emoji,radiocane/noto-emoji,googlei18n/noto-emoji,googlei18n/noto-emoji