patch 8.1.0667: textprop test leaves file behind

Problem:    Textprop test leaves file behind.
Solution:   Delete the file. (Dominique Pelle, closes #3743)
diff --git a/src/testdir/test_textprop.vim b/src/testdir/test_textprop.vim
index e938a58..ad6fd09 100644
--- a/src/testdir/test_textprop.vim
+++ b/src/testdir/test_textprop.vim
@@ -307,5 +307,5 @@
 
   " clean up
   call StopVimInTerminal(buf)
-  call delete('Xtest_folds_with_rnu')
+  call delete('XtestProp')
 endfunc