patch 8.2.2972: "%bd" tries to delete popup window buffers, which fails

Problem:    "%bd" tries to delete popup window buffers, which fails. (Ralf
            Schandl)
Solution:   Do not try to delete a popup window buffer. (closes #8349)
diff --git a/src/testdir/test_popupwin.vim b/src/testdir/test_popupwin.vim
index 13957e5..faadfe2 100644
--- a/src/testdir/test_popupwin.vim
+++ b/src/testdir/test_popupwin.vim
@@ -3918,5 +3918,11 @@
   call delete('XtestPropNotVisble')
 endfunction
 
+func Test_bufdel_skips_popupwin_buffer()
+    let id = popup_create("Some text", {})
+    %bd
+    call popup_close(id)
+endfunc
+
 
 " vim: shiftwidth=2 sts=2