patch 9.0.0465: cursor moves when cmdwin is closed when 'splitscroll' is off

Problem:    Cursor moves when cmdwin is closed when 'splitscroll' is off.
Solution:   Temporarily set 'splitscroll' when jumping back to the original
            window. (closes #11128)

Author: mityu

src/ex_getln.c

@@ -4405,6 +4405,7 @@ open_cmdwin(void)
     int			save_restart_edit = restart_edit;
     int			save_State = State;
     int			save_exmode = exmode_active;
+    int			save_p_spsc;
 #ifdef FEAT_RIGHTLEFT
     int			save_cmdmsg_rl = cmdmsg_rl;
 #endif
@@ -4643,7 +4644,11 @@ open_cmdwin(void)
 	// First go back to the original window.
 	wp = curwin;
 	set_bufref(&bufref, curbuf);
+
+	save_p_spsc = p_spsc;
+	p_spsc = TRUE;
 	win_goto(old_curwin);
+	p_spsc = save_p_spsc;
 
 	// win_goto() may trigger an autocommand that already closes the
 	// cmdline window.

src/testdir/test_window_cmd.vim

@@ -1734,9 +1734,13 @@ func Test_splitscroll_with_splits()
               above copen | wincmd j
               call assert_equal(win_screenpos(0)[0] - tabline, line("w0"))
 
-              " No scroll when opening cmdwin
-              only | norm ggLq:
+              " No scroll when opening cmdwin, and no cursor move when closing
+              " cmdwin.
+              only | norm ggL
+              let curpos = getcurpos()
+              norm q:
               call assert_equal(1, line("w0"))
+              call assert_equal(curpos, getcurpos())
 
               " Scroll when cursor becomes invalid in insert mode
               norm Lic

src/version.c

@@ -703,6 +703,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    465,
 /**/
     464,
 /**/