patch 8.1.1192: mode is not cleared when leaving Insert mode with mapped Esc

Problem:    Mode is not cleared when leaving Insert mode with mapped Esc.
Solution:   Clear the mode when redraw_cmdline is set. (closes #4269)
diff --git a/src/testdir/test_messages.vim b/src/testdir/test_messages.vim
index 2d1d6d9..5708183 100644
--- a/src/testdir/test_messages.vim
+++ b/src/testdir/test_messages.vim
@@ -125,3 +125,31 @@
   exe buf . 'bwipe!'
   call delete(testfile)
 endfunc
+
+func Test_mode_message_at_leaving_insert_with_esc_mapped()
+  if !has('terminal') || has('gui_running')
+    return
+  endif
+
+  " Set custom statusline built by user-defined function.
+  let testfile = 'Xtest.vim'
+  call writefile([
+        \ 'set laststatus=2',
+        \ 'inoremap <Esc> <Esc>00',
+        \ ], testfile)
+
+  let rows = 10
+  let buf = term_start([GetVimProg(), '--clean', '-S', testfile], {'term_rows': rows})
+  call term_wait(buf, 200)
+  call assert_equal('run', job_status(term_getjob(buf)))
+
+  call term_sendkeys(buf, "i")
+  call WaitForAssert({-> assert_match('^-- INSERT --\s*$', term_getline(buf, rows))})
+  call term_sendkeys(buf, "\<Esc>")
+  call WaitForAssert({-> assert_match('^\s*$', term_getline(buf, rows))})
+
+  call term_sendkeys(buf, ":qall!\<CR>")
+  call WaitForAssert({-> assert_equal('dead', job_status(term_getjob(buf)))})
+  exe buf . 'bwipe!'
+  call delete(testfile)
+endfunc