patch 9.0.1606: using freed memory when 'foldcolumn' is set

Problem:    Using freed memory when 'foldcolumn' is set.
Solution:   Save extra pointer to free it later. (closes #12492)
diff --git a/src/testdir/test_fold.vim b/src/testdir/test_fold.vim
index e0119c4..398a0c2 100644
--- a/src/testdir/test_fold.vim
+++ b/src/testdir/test_fold.vim
Binary files differ