Don't apply GPOS if applying morx
That's what Apple does, and it wouldn't degrade our OpenType performance.
Part of https://github.com/harfbuzz/harfbuzz/issues/1348
diff --git a/src/hb-ot-shape.cc b/src/hb-ot-shape.cc
index 00d4c0b..ccee8d3 100644
--- a/src/hb-ot-shape.cc
+++ b/src/hb-ot-shape.cc
@@ -126,7 +126,7 @@
if (hb_options ().aat && hb_aat_layout_has_positioning (face))
plan.apply_kerx = true;
- else if (!disable_gpos && hb_ot_layout_has_positioning (face))
+ else if (!apply_morx && !disable_gpos && hb_ot_layout_has_positioning (face))
plan.apply_gpos = true;
else if (hb_aat_layout_has_positioning (face))
plan.apply_kerx = true;
