patch 8.2.4052: not easy to resize a window from a plugin

Problem:    Not easy to resize a window from a plugin.
Solution:   Add win_move_separator() and win_move_statusline() functions.
            (Daniel Steinberg, closes #9486)
diff --git a/src/evalfunc.c b/src/evalfunc.c
index 949bab8..3905740 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -2398,6 +2398,10 @@
 			ret_list_number,    f_win_id2tabwin},
     {"win_id2win",	1, 1, FEARG_1,	    arg1_number,
 			ret_number,	    f_win_id2win},
+    {"win_move_separator", 2, 2, FEARG_1,   arg2_number,
+			ret_number_bool,    f_win_move_separator},
+    {"win_move_statusline", 2, 2, FEARG_1,  arg2_number,
+			ret_number_bool,    f_win_move_statusline},
     {"win_screenpos",	1, 1, FEARG_1,	    arg1_number,
 			ret_list_number,    f_win_screenpos},
     {"win_splitmove",   2, 3, FEARG_1,	    arg3_number_number_dict,