vim-patch:9.1.1951: tests: Test_windows_external_cmd_in_cwd() only run in huge builds

Problem:  tests: Test_windows_external_cmd_in_cwd() is only run in huge
          builds (after 9.1.1947).
Solution: Move it to test_system.vim so that it is run in normal builds.

closes: vim/vim#18853

2c164f02c6

test/old/testdir/test_system.vim

@@ -141,4 +141,42 @@ func Test_system_with_shell_quote()
   endtry
 endfunc
 
+" Check that Vim does not execute anything from current directory
+func Test_windows_external_cmd_in_cwd()
+  CheckMSWindows
+
+  " just in case
+  call system('rd /S /Q Xfolder')
+  call mkdir('Xfolder', 'R')
+  cd Xfolder
+
+  let contents = ['@echo off', 'echo filename1.txt:1:AAAA']
+  call writefile(contents, 'findstr.cmd')
+
+  let file1 = ['AAAA', 'THIS FILE SHOULD NOT BE FOUND']
+  let file2 = ['BBBB', 'THIS FILE SHOULD BE FOUND']
+
+  call writefile(file1, 'filename1.txt')
+  call writefile(file2, 'filename2.txt')
+
+  if has('quickfix')
+    " use silent to avoid hit-enter-prompt
+    sil grep BBBB filename*.txt
+    call assert_equal('filename2.txt', @%)
+  endif
+
+  let output = system('findstr BBBB filename*')
+  " Match trailing newline byte
+  call assert_match('filename2.txt:BBBB.', output)
+
+  if has('gui')
+    set guioptions+=!
+    let output = system('findstr BBBB filename*')
+    call assert_match('filename2.txt:BBBB.', output)
+  endif
+
+  cd -
+  set guioptions&
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab