refine window batch script initializing

z.cmd

@@ -1,10 +1,8 @@
 @echo off
 setlocal EnableDelayedExpansion
 
-set "HomeDir=%~dp0"
-set "PathSave=%PATH%"
 set "LuaExe=lua"
-set "LuaScript=%HomeDir%z.lua"
+set "LuaScript=%~dp0z.lua"
 set "MatchType=-n"
 set "StrictSub=-n"
 set "RunMode=-n"

z.lua

@@ -2721,8 +2721,6 @@ function z_windows_init(opts)
 	else
 		print('@echo off')
 		print('setlocal EnableDelayedExpansion')
-		print('set "HomeDir=%~dp0"') -- So that Lua can find the z.lua file.
-		print('set "PathSave=%PATH%"')
 		print('set "LuaExe=' .. os.interpreter() .. '"')
 		print('set "LuaScript=' .. os.scriptname() .. '"')
 		print(script_init_cmd)