vim-patch:8.1.2067: no tests for SafeState and SafeStateAgain

Problem:    No tests for SafeState and SafeStateAgain.
Solution:   Add tests.

cadbe1b1fb

This test is quite useless. Don't port to Lua.

Co-authored-by: Bram Moolenaar <Bram@vim.org>

test/old/testdir/test_autocmd.vim

@@ -2959,6 +2959,36 @@ func Test_autocmd_in_try_block()
   au! BufEnter
 endfunc
 
+func Test_autocmd_SafeState()
+  CheckRunVimInTerminal
+
+  let lines =<< trim END
+	let g:safe = 0
+	let g:again = ''
+	au SafeState * let g:safe += 1
+	au SafeStateAgain * let g:again ..= 'x'
+	func CallTimer()
+	  call timer_start(10, {id -> execute('let g:again ..= "t"')})
+	endfunc
+  END
+  call writefile(lines, 'XSafeState')
+  let buf = RunVimInTerminal('-S XSafeState', #{rows: 6})
+
+  call term_sendkeys(buf, ":echo g:safe\<CR>")
+  call WaitForAssert({-> assert_match('^2 ', term_getline(buf, 6))}, 1000)
+
+  call term_sendkeys(buf, ":echo g:again\<CR>")
+  call WaitForAssert({-> assert_match('^xxxx', term_getline(buf, 6))}, 1000)
+
+  call term_sendkeys(buf, ":let g:again = ''\<CR>:call CallTimer()\<CR>")
+  call term_wait(buf)
+  call term_sendkeys(buf, ":echo g:again\<CR>")
+  call WaitForAssert({-> assert_match('xtx', term_getline(buf, 6))}, 1000)
+
+  call StopVimInTerminal(buf)
+  call delete('XSafeState')
+endfunc
+
 func Test_autocmd_CmdWinEnter()
   CheckRunVimInTerminal
   " There is not cmdwin switch, so