fixed leak exposed by test-ot-extents-cff

src/hb-cff-interp-common.hh

@@ -627,6 +627,9 @@ struct ArgStack : Stack<ARG, 513>
 /* an operator prefixed by its operands in a byte string */
 struct OpStr
 {
+  inline void init (void) {}
+  inline void fini (void) {}
+
   OpCode  op;
   ByteStr str;
 };

src/hb-cff-interp-dict-common.hh

@@ -64,6 +64,10 @@ struct DictValues
 
   inline void fini (void)
   {
+    for (unsigned int i = 0; i < values.len; i++)
+    {
+      values[i].fini ();
+    }
     values.fini ();
   }