Do not enable delayed expansion mode when running cmd.exe

And simplify the argument escaping code. Fix #3764.

This may breaks some existing use cases, but the mode causes too much
trouble when escaping arguments and it makes some things not possible.

  # Now you can pass special characters to rg process without any escaping problems: &|<>()@^%!
  fzf --ansi --disabled --bind "change:reload:rg --column --line-number --no-heading --color=always --smart-case -- {q}"

  # No sudden expansion of the arguments on '!'
  fzf --disabled --preview "echo {q} {n} {}" --query "&|<>()@^%!" --prompt "&|<>()@^%!"

man/man1/fzf.1

@@ -821,7 +821,7 @@ e.g. \fBfzf --multi | fzf --sync\fR
 .B "--with-shell=STR"
 Shell command and flags to start child processes with. On *nix Systems, the
 default value is \fB$SHELL -c\fR if \fB$SHELL\fR is set, otherwise \fBsh -c\fR.
-On Windows, the default value is \fBcmd /v:on/s/c\fR when \fB$SHELL\fR is not
+On Windows, the default value is \fBcmd /s/c\fR when \fB$SHELL\fR is not
 set.
 
 .RS

plugin/fzf.vim

@@ -59,12 +59,9 @@ if s:is_win
     return iconv(a:str, &encoding, 'cp'.s:codepage)
   endfunction
   function! s:wrap_cmds(cmds)
-    return map([
-      \ '@echo off',
-      \ 'setlocal enabledelayedexpansion']
+    return map(['@echo off']
     \ + (has('gui_running') ? ['set TERM= > nul'] : [])
-    \ + (type(a:cmds) == type([]) ? a:cmds : [a:cmds])
-    \ + ['endlocal'],
+    \ + (type(a:cmds) == type([]) ? a:cmds : [a:cmds]),
     \ '<SID>enc_to_cp(v:val."\r")')
   endfunction
 else
@@ -83,8 +80,6 @@ else
   endfunction
 endif
 
-let s:cmd_control_chars = ['&', '|', '<', '>', '(', ')', '@', '^', '!']
-
 function! s:shellesc_cmd(arg)
   let e = '"'
   let slashes = 0
@@ -94,10 +89,6 @@ function! s:shellesc_cmd(arg)
     elseif c ==# '"'
       let e .= repeat('\', slashes + 1)
       let slashes = 0
-    elseif c ==# '%'
-      let e .= '%'
-    elseif index(s:cmd_control_chars, c) >= 0
-      let e .= '^'
     else
       let slashes = 0
     endif

src/util/util_windows.go

@@ -42,7 +42,7 @@ func NewExecutor(withShell string) *Executor {
 		args = args[1:]
 	} else if strings.HasPrefix(basename, "cmd") {
 		shellType = shellTypeCmd
-		args = []string{"/v:on/s/c"}
+		args = []string{"/s/c"}
 	} else if strings.HasPrefix(basename, "pwsh") || strings.HasPrefix(basename, "powershell") {
 		shellType = shellTypePowerShell
 		args = []string{"-NoProfile", "-Command"}
@@ -119,8 +119,6 @@ func escapeArg(s string) string {
 			slashes = 0
 		case '\\':
 			slashes++
-		case '&', '|', '<', '>', '(', ')', '@', '^', '%', '!':
-			b = append(b, '^')
 		case '"':
 			for ; slashes > 0; slashes-- {
 				b = append(b, '\\')