patch 9.0.1035: object members are not being marked as used

Problem:    Object members are not being marked as used, garbage collection
            may free them.
Solution:   Mark object members as used.  Fix reference counting.
diff --git a/src/testdir/test_vim9_class.vim b/src/testdir/test_vim9_class.vim
index 6742ea7..1945db1 100644
--- a/src/testdir/test_vim9_class.vim
+++ b/src/testdir/test_vim9_class.vim
@@ -132,11 +132,10 @@
 	this.col: number
       endclass
 
-      # # FIXME: this works but leaks memory
-      # # use the automatically generated new() method
-      # var pos = TextPosition.new(2, 12)
-      # assert_equal(2, pos.lnum)
-      # assert_equal(12, pos.col)
+      # use the automatically generated new() method
+      var pos = TextPosition.new(2, 12)
+      assert_equal(2, pos.lnum)
+      assert_equal(12, pos.col)
   END
   v9.CheckScriptSuccess(lines)
 enddef