patch 8.2.2147: quickfix window title not updated in all tab pages

Problem:    Quickfix window title not updated in all tab pages.
Solution:   Update the quickfix window title in all tab pages. (Yegappan
            Lakshmanan, closes #7481, closes #7466)
diff --git a/src/testdir/test_quickfix.vim b/src/testdir/test_quickfix.vim
index d89508f..888c2f4 100644
--- a/src/testdir/test_quickfix.vim
+++ b/src/testdir/test_quickfix.vim
@@ -4165,6 +4165,30 @@
   call setqflist([], 'r', {'items' : [{'filename' : 'a.c', 'lnum' : 10}]})
   call assert_equal('Errors', w:quickfix_title)
   cclose
+
+  " Switching to another quickfix list in one tab page should update the
+  " quickfix window title and statusline in all the other tab pages also
+  call setqflist([], 'f')
+  %bw!
+  cgetexpr ['file_one:1:1: error in the first quickfix list']
+  call setqflist([], 'a', {'title': 'first quickfix list'})
+  cgetexpr ['file_two:2:1: error in the second quickfix list']
+  call setqflist([], 'a', {'title': 'second quickfix list'})
+  copen
+  wincmd t
+  tabnew two
+  copen
+  wincmd t
+  colder
+  call assert_equal('first quickfix list', gettabwinvar(1, 2, 'quickfix_title'))
+  call assert_equal('first quickfix list', gettabwinvar(2, 2, 'quickfix_title'))
+  call assert_equal(1, tabpagewinnr(1))
+  call assert_equal(1, tabpagewinnr(2))
+  tabnew
+  call setqflist([], 'a', {'title': 'new quickfix title'})
+  call assert_equal('new quickfix title', gettabwinvar(1, 2, 'quickfix_title'))
+  call assert_equal('new quickfix title', gettabwinvar(2, 2, 'quickfix_title'))
+  %bw!
 endfunc
 
 func Test_lbuffer_with_bwipe()