patch 8.2.2132: padding not drawn properly for popup window with title

Problem:    Padding not drawn properly for popup window with title.
Solution:   Draw the padding below the title. (closes #7460)
diff --git a/src/testdir/test_popupwin.vim b/src/testdir/test_popupwin.vim
index 3f13b26..cf9536f 100644
--- a/src/testdir/test_popupwin.vim
+++ b/src/testdir/test_popupwin.vim
@@ -1766,6 +1766,16 @@
   call term_sendkeys(buf, ":\<CR>")
   call VerifyScreenDump(buf, 'Test_popupwin_longtitle_2', {})
 
+  call term_sendkeys(buf, ":call popup_clear()\<CR>")
+  call term_sendkeys(buf, ":call popup_create(['aaa', 'bbb'], #{title: 'Title', minwidth: 12, padding: [2, 2, 2, 2]})\<CR>")
+  call term_sendkeys(buf, ":\<CR>")
+  call VerifyScreenDump(buf, 'Test_popupwin_longtitle_3', {})
+
+  call term_sendkeys(buf, ":call popup_clear()\<CR>")
+  call term_sendkeys(buf, ":call popup_create(['aaa', 'bbb'], #{title: 'Title', minwidth: 12, border: [], padding: [2, 2, 2, 2]})\<CR>")
+  call term_sendkeys(buf, ":\<CR>")
+  call VerifyScreenDump(buf, 'Test_popupwin_longtitle_4', {})
+
   " clean up
   call StopVimInTerminal(buf)
   call delete('XtestPopupTitle')