[test] Fix test-name-table.cc leak issue

Spotted it accidentally but wanted to see if is anything serious so went for fixing it
diff --git a/src/test-name-table.cc b/src/test-name-table.cc
index e40be6e..518e4eb 100644
--- a/src/test-name-table.cc
+++ b/src/test-name-table.cc
@@ -63,5 +63,7 @@
     printf ("%s\n", buf);
   }
 
+  hb_face_destroy (face);
+
   return count ? 0 : 1;
 }