OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=30823
Crash type: Bad-cast
Crash state:
Bad-cast to tt_cmap_t' (aka 'struct _tt_cmap')_cairo_truetype_index_to_ucs4
_cairo_sub_font_glyph_lookup_unicode
_cairo_sub_font_map_glyph