Fix extra semicolon issues and test that on CI (#1330)

diff --git a/src/hb-ot-layout-gsubgpos.hh b/src/hb-ot-layout-gsubgpos.hh
index 03fdac2..c4af420 100644
--- a/src/hb-ot-layout-gsubgpos.hh
+++ b/src/hb-ot-layout-gsubgpos.hh
@@ -271,7 +271,7 @@
 	     syllable arg1(0),
 #undef arg1
 	     match_func (nullptr),
-	     match_data (nullptr) {};
+	     match_data (nullptr) {}
 
     typedef bool (*match_func_t) (hb_codepoint_t glyph_id, const HBUINT16 &value, const void *data);