New formula: harfbuzz 0.9.12

An OpenType text shaping engine, required by pango 1.32+

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
pango 1.32.6

 - Updating test
 - Add dep on harfbuzz

Closes #16900.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
fontconfig 2.10.91
pango: fix building xft backend

This is required to get Gtk+ to build correctly.