patch 9.0.0488: cursor wrong with virtual text "above" and 'showbreak'

Problem:    Cursor in wrong position with virtual text "above" and
            'showbreak'.
Solution:   Take the first character column into account. (closes #11149)
diff --git a/src/testdir/test_textprop.vim b/src/testdir/test_textprop.vim
index 259ff9c..1c32cbc 100644
--- a/src/testdir/test_textprop.vim
+++ b/src/testdir/test_textprop.vim
@@ -2874,6 +2874,11 @@
   call term_sendkeys(buf, "g0")
   call VerifyScreenDump(buf, 'Test_prop_with_text_above_1b', {})
 
+  call term_sendkeys(buf, ":set showbreak=>>\<CR>")
+  call term_sendkeys(buf, "ggll")
+  call VerifyScreenDump(buf, 'Test_prop_with_text_above_1c', {})
+  call term_sendkeys(buf, ":set showbreak=\<CR>")
+
   call term_sendkeys(buf, "ggI")
   call VerifyScreenDump(buf, 'Test_prop_with_text_above_2', {})
   call term_sendkeys(buf, "inserted \<Esc>")