Log Message:
harfbuzz: Update to 2.6.5

Overview of changes leading to 2.6.5
Friday, April 17, 2020
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- Add experimental meson build system.  Autotools is still the primary
  and supported build system.
- AAT is now always preferred for horizontal scripts when both AAT and OT
  layout tables exist at the same time.
- Subsetter improvements.
- New API:
+hb_ft_font_lock_face()
+hb_ft_font_unlock_face()