Improve options support about bach HOT 2 CLOSED

public static void main(String... args) {
  JavaShellBuilder builder = new JavaShellBuilder();
  builder.set(Level.INFO);

  builder.execute("javac", "T.java");

  Tool.JavacOptions options = builder.tool.new JavacOptions();
  options.additionalArguments = List.of("-g", "-Xlint");
  options.encoding = StandardCharsets.ISO_8859_1;
  options.parameters = false;
  Command command = builder.command("javac", "--release", "9", "-nowarn"); // one-shot options
  command.addOptions(options); // re-usable options
  command.add("T.java");
  command.execute();

  builder.tool.defaultJavacOptions = () -> options; // or return "null" to use no default options
  builder.compile();
}