patch 8.1.1907: wrong position for info popup with scrollbar on the left

Problem:    Wrong position for info popup with scrollbar on the left.
Solution:   Take the scrollbar into account.
diff --git a/src/testdir/test_popupwin.vim b/src/testdir/test_popupwin.vim
index 6c1ac52..358da6d 100644
--- a/src/testdir/test_popupwin.vim
+++ b/src/testdir/test_popupwin.vim
@@ -2275,6 +2275,11 @@
   call term_sendkeys(buf, "\<C-N>\<C-N>")
   call VerifyScreenDump(buf, 'Test_popupwin_infopopup_4', {})
 
+  " info on the left with scrollbar
+  call term_sendkeys(buf, "test text test text\<C-X>\<C-U>")
+  call term_sendkeys(buf, "\<C-N>\<C-N>")
+  call VerifyScreenDump(buf, 'Test_popupwin_infopopup_5', {})
+
   call StopVimInTerminal(buf)
   call delete('XtestInfoPopup')
 endfunc