patch 8.2.4789: cursor pos wrong when using :redraw while editing the cmdline

Problem:    The cursor may be in the in wrong place when using :redraw while
            editing the cmdline.
Solution:   When editing the command line let :redraw update the command line
            too. (closes #10210)
diff --git a/src/testdir/test_cmdline.vim b/src/testdir/test_cmdline.vim
index 8baa1ac..8d556fa 100644
--- a/src/testdir/test_cmdline.vim
+++ b/src/testdir/test_cmdline.vim
@@ -193,6 +193,28 @@
   call delete('XTest_wildmenu')
 endfunc
 
+func Test_redraw_in_autocmd()
+  CheckScreendump
+
+  let lines =<< trim END
+      set cmdheight=2
+      autocmd CmdlineChanged * redraw
+  END
+  call writefile(lines, 'XTest_redraw')
+
+  let buf = RunVimInTerminal('-S XTest_redraw', {'rows': 8})
+  call term_sendkeys(buf, ":for i in range(3)\<CR>")
+  call VerifyScreenDump(buf, 'Test_redraw_in_autocmd_1', {})
+
+  call term_sendkeys(buf, "let i =")
+  call VerifyScreenDump(buf, 'Test_redraw_in_autocmd_2', {})
+
+  " clean up
+  call term_sendkeys(buf, "\<CR>")
+  call StopVimInTerminal(buf)
+  call delete('XTest_redraw')
+endfunc
+
 func Test_map_completion()
   call feedkeys(":map <unique> <si\<Tab>\<Home>\"\<CR>", 'xt')
   call assert_equal('"map <unique> <silent>', getreg(':'))