patch 8.2.1998: terminal Cmd test sometimes fails to close popup

Problem:    Terminal Cmd test sometimes fails to close popup.
Solution:   Add "term_finish" option.

src/testdir/test_terminal.vim

@@ -1259,15 +1259,14 @@ func Test_terminal_popup_insert_cmd()
 
   inoremap <F3> <Cmd>call StartTermInPopup()<CR>
   func StartTermInPopup()
-    call term_start(['/bin/sh', '-c', 'cat'], #{hidden: v:true})->popup_create(#{highlight: 'Pmenu'})
+    call term_start(['/bin/sh', '-c', 'cat'], #{hidden: v:true, term_finish: 'close'})->popup_create(#{highlight: 'Pmenu'})
   endfunc
   call feedkeys("i\<F3>")
   sleep 10m
   call assert_equal('n', mode())
 
   call feedkeys("\<C-D>", 'xt')
-  sleep 20m
-  call feedkeys(":q\<CR>", 'xt')
+  sleep 50m
   delfunc StartTermInPopup
   iunmap <F3>
 endfunc

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1998,
 /**/
     1997,
 /**/