How to implement fork join_none block using fork join_any and fork join_any using fork join_none?

SystemVerilog
,
2

It is certainly possible to implement fork/join_none with join_any by inserting a null statement.

module top;
   initial begin
      fork
	 #10 $display("#10");
	 #20 $display("#20");
	 begin end
      join_any
      $display("done fork");
   end
endmodule

And fork/join_any can be implemented with fork/join_none by adding an event.

module top;
   event any;
   initial begin
      fork
	 begin #10 $display("#10"); ->any; end
	 begin #20 $display("#20"); ->any; end
      join_none
      @any;
      $display("done fork");
   end
endmodule

Is this question just to help your understand these fork constructs, or is there some other situation you are trying to avoid by replacing one construct with another? I would need to know more about that situation to help you further. There are subtle differences other constructs like disable fork and wait fork.