patch 8.1.1806: test for display updating doesn't check without statusline

Problem:    Test for display updating doesn't check without statusline.
Solution:   Add screenshots without a status line.

src/testdir/dumps/Test_scroll_no_region_4.dump

@@ -0,0 +1,10 @@
+|1+0&#ffffff0| @73
+|2| @73
+>3| @73
+|4| @73
+|5| @73
+|6| @73
+|7| @73
+|8| @73
+|9| @73
+|:|s|e|t| |l|a|s|t|s|t|a|t|u|s|=|0| @39|3|,|1| @10|T|o|p| 

src/testdir/dumps/Test_scroll_no_region_5.dump

@@ -0,0 +1,10 @@
+|1+0&#ffffff0| @73
+|2| @73
+>4| @73
+|5| @73
+|6| @73
+|7| @73
+|8| @73
+|9| @73
+|1|0| @72
+@57|3|,|1| @10|T|o|p| 

src/testdir/dumps/Test_scroll_no_region_6.dump

@@ -0,0 +1,10 @@
+|1+0&#ffffff0| @73
+|2| @73
+|4| @73
+|5| @73
+>3| @73
+|6| @73
+|7| @73
+|8| @73
+|9| @73
+@57|5|,|1| @10|T|o|p| 

src/testdir/test_display.vim

@@ -88,6 +88,17 @@ func Test_scroll_without_region()
   call term_sendkeys(buf, ":4put\<cr>")
   call VerifyScreenDump(buf, 'Test_scroll_no_region_3', {})
 
+  call term_sendkeys(buf, ":undo\<cr>")
+  call term_sendkeys(buf, ":undo\<cr>")
+  call term_sendkeys(buf, ":set laststatus=0\<cr>")
+  call VerifyScreenDump(buf, 'Test_scroll_no_region_4', {})
+
+  call term_sendkeys(buf, ":3delete\<cr>")
+  call VerifyScreenDump(buf, 'Test_scroll_no_region_5', {})
+
+  call term_sendkeys(buf, ":4put\<cr>")
+  call VerifyScreenDump(buf, 'Test_scroll_no_region_6', {})
+
   " clean up
   call StopVimInTerminal(buf)
   call delete('Xtestscroll')

src/version.c

@@ -773,6 +773,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1806,
 /**/
     1805,
 /**/