patch 9.1.0730: Crash with cursor-screenline and narrow window

Problem:  Crash with cursor-screenline and narrow window
          (elig0n)
Solution: Don't set right_col when width2 is 0 (zeertzjq).

fixes: #15677
closes: #15678

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_cursorline.vim b/src/testdir/test_cursorline.vim
index bdde670..d258111 100644
--- a/src/testdir/test_cursorline.vim
+++ b/src/testdir/test_cursorline.vim
@@ -309,6 +309,17 @@
   call StopVimInTerminal(buf)
 endfunc
 
+func Test_cursorline_screenline_zero_width()
+  CheckOption foldcolumn
+
+  set cursorline culopt=screenline winminwidth=1 foldcolumn=1
+  " This used to crash Vim
+  1vnew | redraw
+
+  bwipe!
+  set cursorline& culopt& winminwidth& foldcolumn&
+endfunc
+
 func Test_cursorline_cursorbind_horizontal_scroll()
   CheckScreendump