patch 9.0.1243: :setglobal cannot use script-local function for "expr" option

Problem:    :setglobal cannot use script-local function for "expr" option.
Solution:   Use the pointer to the option value properly. (closes #11883)
diff --git a/src/testdir/test_fold.vim b/src/testdir/test_fold.vim
index 7f75e91..a0291a0 100644
--- a/src/testdir/test_fold.vim
+++ b/src/testdir/test_fold.vim
Binary files differ