patch 9.1.0572: cannot specify tab page closing behaviour

Problem:  cannot specify tab page closing behaviour
          (Gianluca Pacchiella)
Solution: Add the 'tabclose' option (LemonBoy).

fixes: #5967
closes: #15204

Signed-off-by: LemonBoy <thatlemon@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_options.vim b/src/testdir/test_options.vim
index fbfbaae..02f5d7e 100644
--- a/src/testdir/test_options.vim
+++ b/src/testdir/test_options.vim
@@ -548,6 +548,9 @@
   call assert_equal('sync', getcompletion('set swapsync=', 'cmdline')[1])
   call assert_equal('usetab', getcompletion('set switchbuf=', 'cmdline')[1])
   call assert_equal('ignore', getcompletion('set tagcase=', 'cmdline')[1])
+  if exists('+tabclose')
+    call assert_equal('left uselast', join(sort(getcompletion('set tabclose=', 'cmdline'))), ' ')
+  endif
   if exists('+termwintype')
     call assert_equal('conpty', getcompletion('set termwintype=', 'cmdline')[1])
   endif
@@ -1407,7 +1410,8 @@
   set nowrite
   call assert_fails('write Xwrfile', 'E142:')
   set write
-  close!
+  " close swapfile
+  bw!
 endfunc
 
 " Test for 'buftype' option