patch 8.2.0470: Test_confirm_cmd_cancel() can fail on a slow system

Problem:    Test_confirm_cmd_cancel() can fail on a slow system.
Solution:   Use WaitForAssert(). (Ozaki Kiichi, closes #5861)

Author: brammool

src/testdir/test_excmd.vim

@@ -259,7 +259,7 @@ func Test_confirm_cmd_cancel()
   call WaitForAssert({-> assert_match('^\[Y\]es, (N)o, (C)ancel: *$',
         \ term_getline(buf, 20))}, 1000)
   call term_sendkeys(buf, "C")
-  call term_wait(buf, 50)
+  call WaitForAssert({-> assert_equal('', term_getline(buf, 20))}, 1000)
   call term_sendkeys(buf, ":confirm close\n")
   call WaitForAssert({-> assert_match('^\[Y\]es, (N)o, (C)ancel: *$',
         \ term_getline(buf, 20))}, 1000)

src/version.c

@@ -738,6 +738,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    470,
 /**/
     469,
 /**/