patch 8.2.4456: terminal test may fail on some machines

Problem:    Terminal test may fail on some machines.
Solution:   Increase wait time. (Zdenek Dohnal, closes #9834)

src/testdir/test_terminal.vim

@@ -715,7 +715,8 @@ endfunction
 func Test_terminal_noblock()
   let g:test_is_flaky = 1
   let buf = term_start(&shell)
-  let wait_time = 5000
+  " Starting a terminal can be slow, esp. on busy CI machines.
+  let wait_time = 7500
   let letters = 'abcdefghijklmnopqrstuvwxyz'
   if has('bsd') || has('mac') || has('sun')
     " The shell or something else has a problem dealing with more than 1000

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4456,
 /**/
     4455,
 /**/