[gpos] in PairPos, always advance next-glyph by one only

This goes against the spec.

https://github.com/harfbuzz/harfbuzz/issues/3824
diff --git a/src/OT/Layout/GPOS/PairPosFormat2.hh b/src/OT/Layout/GPOS/PairPosFormat2.hh
index 83b093b..b1b2915 100644
--- a/src/OT/Layout/GPOS/PairPosFormat2.hh
+++ b/src/OT/Layout/GPOS/PairPosFormat2.hh
@@ -243,8 +243,6 @@
 
 
     buffer->idx = skippy_iter.idx;
-    if (len2)
-      buffer->idx++;
 
     return_trace (true);
   }
diff --git a/src/OT/Layout/GPOS/PairSet.hh b/src/OT/Layout/GPOS/PairSet.hh
index aa48d93..e2de81d 100644
--- a/src/OT/Layout/GPOS/PairSet.hh
+++ b/src/OT/Layout/GPOS/PairSet.hh
@@ -128,8 +128,6 @@
 
       if (applied_first || applied_second)
         buffer->unsafe_to_break (buffer->idx, pos + 1);
-      if (len2)
-        pos++;
 
       buffer->idx = pos;
       return_trace (true);