parse.y: use rb_ary_tmp_new_fill

* parse.y (coverage): use rb_ary_tmp_new_fill() instead of setting
  internal structure directly.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47296 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

parse.y

@@ -5313,11 +5313,7 @@ coverage(VALUE fname, int n)
 {
     VALUE coverages = rb_get_coverages();
     if (RTEST(coverages) && RBASIC(coverages)->klass == 0) {
-	VALUE lines = rb_ary_new2(n);
-	int i;
-	RBASIC_CLEAR_CLASS(lines);
-	for (i = 0; i < n; i++) RARRAY_ASET(lines, i, Qnil);
-	RARRAY(lines)->as.heap.len = n;
+	VALUE lines = rb_ary_tmp_new_fill(n);
 	rb_hash_aset(coverages, fname, lines);
 	return lines;
     }