patch 9.0.0954: cannot detect whether modifyOtherKeys is enabled

Problem:    Cannot detect whether modifyOtherKeys is enabled.
Solution:   Use XTQMODKEYS introduced by xterm version 377 to request the
            modifyOtherKeys level.  Update the keycode check results.
diff --git a/src/testdir/test_modeless.vim b/src/testdir/test_modeless.vim
index 3736f98..281c248 100644
--- a/src/testdir/test_modeless.vim
+++ b/src/testdir/test_modeless.vim
@@ -5,6 +5,7 @@
 CheckNotGui
 CheckUnix
 
+source shared.vim
 source mouse.vim
 
 " Test for modeless characterwise selection (single click)
@@ -15,10 +16,15 @@
   let save_ttymouse = &ttymouse
   call test_override('no_query_mouse', 1)
   set mouse=a term=xterm mousetime=200
+  call WaitForResponses()
+
   new
   call setline(1, ['one two three', 'foo bar baz'])
   redraw!
 
+  " Wait a bit for any terminal responses to get processed.
+  sleep 50m
+
   for ttymouse_val in g:Ttymouse_values + g:Ttymouse_dec
     let msg = 'ttymouse=' .. ttymouse_val
     exe 'set ttymouse=' .. ttymouse_val
@@ -250,6 +256,8 @@
   let save_ttymouse = &ttymouse
   call test_override('no_query_mouse', 1)
   set mouse=a term=xterm mousetime=200
+  call WaitForResponses()
+
   new
   call setline(1, ['one two three', 'foo bar baz'])
   redraw!
@@ -330,6 +338,8 @@
   let save_ttymouse = &ttymouse
   call test_override('no_query_mouse', 1)
   set mouse=a term=xterm mousetime=200
+  call WaitForResponses()
+
   new
   call setline(1, ['one two three', 'foo bar baz'])
   redraw!