[dndxc] Add option when dump ast. (#5266)

* [dndxc] Add option when dump ast.

This will allow dump ast to add option like -HV 2021.

tools/clang/tools/dotnetc/EditorForm.cs

@@ -624,7 +624,12 @@ namespace MainNs
                 {
                     try
                     {
-                        var result = compiler.Compile(source, fileName, fileVars.Entry, fileVars.Target, new string[] { "-ast-dump" }, 1, null, 0, library.CreateIncludeHandler());
+                        List<string> args = new List<string>();
+                        args.Add("-ast-dump");
+                        args.AddRange(tbOptions.Text.Split());
+                        var result = compiler.Compile(source, fileName, fileVars.Entry,
+                            fileVars.Target, args.ToArray(), args.Count,
+                            null, 0, library.CreateIncludeHandler());
                         if (result.GetStatus() == 0)
                         {
                             this.ASTDumpBox.Text = GetStringFromBlob(result.GetResult());