patch 9.0.0964: status line not redrawn when 'splitkeep' is "screen"

Problem:    Status line of other window not redrawn when dragging it when
            'splitkeep' is set to "screen".
Solution:   Set w_redr_status earlier. (Luuk van Baal, closes #11635,
            closes #11632)

src/testdir/test_window_cmd.vim

@@ -1895,4 +1895,22 @@ function Test_splitkeep_fold()
   call VerifyScreenDump(buf, 'Test_splitkeep_fold_4', {})
 endfunction
 
+function Test_splitkeep_status()
+  CheckScreendump
+
+  let lines =<< trim END
+    call setline(1, ['a', 'b', 'c'])
+    set nomodified
+    set splitkeep=screen
+    let win = winnr()
+    wincmd s
+    wincmd j
+  END
+  call writefile(lines, 'XTestSplitkeepStatus', 'D')
+  let buf = RunVimInTerminal('-S XTestSplitkeepStatus', #{rows: 10})
+
+  call term_sendkeys(buf, ":call win_move_statusline(win, 1)\<CR>")
+  call VerifyScreenDump(buf, 'Test_splitkeep_status_1', {})
+endfunction
+
 " vim: shiftwidth=2 sts=2 expandtab