patch 9.2.0540: tests: Test_mswin_event_mouse is flaky

Problem:  tests: Test_mswin_event_mouse is flaky
Solution: Mark as flaky (Ken Takata)

Test_mswin_event_mouse is flaky in console:
https://github.com/vim/vim-win32-installer/issues/446#issuecomment-4538212367

closes: #20331

Signed-off-by: K.Takata <kentkt@csc.jp>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/testdir/test_mswin_event.vim

@@ -704,6 +704,10 @@ func Test_mswin_event_mouse()
   CheckMSWindows
   new
 
+  if !has('gui_running')
+    let g:test_is_flaky = 1
+  endif
+
   set mousemodel=extend
   call test_override('no_query_mouse', 1)
   call WaitForResponses()

src/version.c

@@ -729,6 +729,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    540,
 /**/
     539,
 /**/