patch 9.0.1257: code style is not check in test scripts

Problem:    Code style is not check in test scripts.
Solution:   Add basic code style check for test files.

Author: brammool

src/testdir/keycode_check.vim

@@ -4,8 +4,8 @@ vim9script
 #
 # Usage:  vim -u NONE -S keycode_check.vim
 #
-# Author: 	Bram Moolenaar
-# Last Update: 	2022 Nov 15
+# Author:	Bram Moolenaar
+# Last Update:	2022 Nov 15
 #
 # The codes are stored in the file "keycode_check.json", so that you can
 # compare the results of various terminals.
@@ -449,7 +449,7 @@ enddef
 # The main loop
 while true
   var action = inputlist(['Select operation:',
-    			'1. List results',
+			'1. List results',
 			'2. Add results for a new terminal',
 			'3. Replace results',
 			'4. Clear results',

src/testdir/runtest.vim

@@ -59,7 +59,7 @@ if has('gui_running')
 endif
 
 " Check that the screen size is at least 24 x 80 characters.
-if &lines < 24 || &columns < 80 
+if &lines < 24 || &columns < 80
   let error = 'Screen size too small! Tests require at least 24 lines with 80 characters, got ' .. &lines .. ' lines with ' .. &columns .. ' characters'
   echoerr error
   split test.log

src/testdir/setup.vim

@@ -20,7 +20,7 @@ if has('packages')
   let &packpath = &rtp
 endif
 
-" Only when the +eval feature is present. 
+" Only when the +eval feature is present.
 if 1
   " Make sure the .Xauthority file can be found after changing $HOME.
   if $XAUTHORITY == ''

src/testdir/summarize.vim

@@ -33,7 +33,7 @@ if 1
     silent %s/^SKIPPED \zs.*/\=Count(submatch(0), 'skipped')/egn
     silent %s/^\(\d\+\)\s\+FAILED:/\=Count(submatch(1), 'failed')/egn
 
-    call extend(output, ["Skipped:"]) 
+    call extend(output, ["Skipped:"])
     call extend(output, skipped_output)
 
     call extend(output, [

src/testdir/test_assert.vim

@@ -190,9 +190,9 @@ func Test_wrong_error_type()
 endfunc
 
 func Test_compare_fail()
-  let s:v = {}          
-  let s:x = {"a": s:v} 
-  let s:v["b"] = s:x   
+  let s:v = {}
+  let s:x = {"a": s:v}
+  let s:v["b"] = s:x
   let s:w = {"c": s:x, "d": ''}
   try
     call assert_equal(s:w, '')

src/testdir/test_autocmd.vim

@@ -269,8 +269,8 @@ func Test_win_tab_autocmd()
   augroup testing
     au WinNew * call add(g:record, 'WinNew')
     au WinClosed * call add(g:record, 'WinClosed')
-    au WinEnter * call add(g:record, 'WinEnter') 
-    au WinLeave * call add(g:record, 'WinLeave') 
+    au WinEnter * call add(g:record, 'WinEnter')
+    au WinLeave * call add(g:record, 'WinLeave')
     au TabNew * call add(g:record, 'TabNew')
     au TabClosed * call add(g:record, 'TabClosed')
     au TabEnter * call add(g:record, 'TabEnter')
@@ -3406,7 +3406,7 @@ endfunc
 
 func Test_Visual_doautoall_redraw()
   call setline(1, ['a', 'b'])
-  new 
+  new
   wincmd p
   call feedkeys("G\<C-V>", 'txn')
   autocmd User Explode ++once redraw
@@ -4121,7 +4121,7 @@ endfunc
 
 func Test_autocmd_split_dummy()
   " Autocommand trying to split a window containing a dummy buffer.
-  auto BufReadPre * exe "sbuf " .. expand("<abuf>") 
+  auto BufReadPre * exe "sbuf " .. expand("<abuf>")
   " Avoid the "W11" prompt
   au FileChangedShell * let v:fcs_choice = 'reload'
   func Xautocmd_changelist()

src/testdir/test_blob.vim

@@ -498,7 +498,7 @@ func Test_blob_read_write()
       call assert_equal(b[-3 :], br5)
       VAR br6 = readblob('Xblob', -3, 2)
       call assert_equal(b[-3 : -2], br6)
-      
+
       #" reading past end of file, empty result
       VAR br1e = readblob('Xblob', 10000)
       call assert_equal(0z, br1e)

src/testdir/test_blockedit.vim

@@ -52,7 +52,7 @@ func Test_blockinsert_autoindent()
   let expected =<< trim END
       vim9script
       var d = {
-      	a: (): asdf => 0,
+	a: (): asdf => 0,
       b: (): asdf => 0,
       c: (): asdf => 0,
       }

src/testdir/test_channel.vim

@@ -20,7 +20,7 @@ endif
 " call ch_logfile('channellog', 'w')
 
 func SetUp()
-  if g:testfunc =~ '_ipv6()$' 
+  if g:testfunc =~ '_ipv6()$'
     let s:localhost = '[::1]:'
     let s:testscript = 'test_channel_6.py'
   elseif g:testfunc =~ '_unix()$'
@@ -1220,7 +1220,7 @@ endfunc
 func Test_pipe_to_buffer_raw()
   let options = {'out_mode': 'raw', 'out_io': 'buffer', 'out_name': 'testout'}
   split testout
-  let job = job_start([s:python, '-c', 
+  let job = job_start([s:python, '-c',
         \ 'import sys; [sys.stdout.write(".") and sys.stdout.flush() for _ in range(10000)]'], options)
   " the job may be done quickly, also accept "dead"
   call assert_match('^\%(dead\|run\)$', job_status(job))

src/testdir/test_cmd_lists.vim

@@ -50,7 +50,7 @@ func Test_cmd_lists()
           \ 'interface',
           \ 'public',
           \ 'static',
-          \ 'this', 
+          \ 'this',
           \ 'type',
           \ '++',
           \ '--',