patch 8.1.2079: popup window test fails without +terminal

Problem:    Popup window test fails without +terminal.
Solution:   Check for the +terminal feature.

src/testdir/test_popupwin.vim

@@ -1993,6 +1993,8 @@ func Test_popupwin_with_buffer()
 endfunc
 
 func Test_popupwin_terminal_buffer()
+  CheckFeature terminal
+
   let ptybuf = term_start(&shell, #{hidden: 1})
   call assert_fails('let winnr = popup_create(ptybuf, #{})', 'E278:')
   exe 'bwipe! ' .. ptybuf

src/version.c

@@ -757,6 +757,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2079,
 /**/
     2078,
 /**/