[subset] Another fixup

I broke this in c31fcf4c58

src/hb-ot-cmap-table.hh

@@ -590,7 +590,7 @@ struct cmap
 
   hb_blob_t * subset (hb_subset_plan_t *plan, hb_face_t *source) const
   {
-    hb_prealloced_array_t<CmapSubtableLongGroup> groups;
+    hb_auto_array_t<CmapSubtableLongGroup> groups;
 
     populate_groups(plan->codepoints, &groups);
 

test/subset/run-tests.py

@@ -42,6 +42,7 @@ def run_test(test):
 		    "--font-file=" + test.font_path,
 		    "--output-file=" + out_file,
 		    "--unicodes=%s" % test.unicodes()]
+	print (' '.join(cli_args))
 	_, return_code = cmd(cli_args)
 
 	if return_code: