gnucash maint: Fix use-after-free crash in utest-Invoice.

[Christopher Lam]

Updated	 via  https://github.com/Gnucash/gnucash/commit/9f6d495c (commit)
	from  https://github.com/Gnucash/gnucash/commit/e9df8d41 (commit)



commit 9f6d495ca1b37106fca6ec6dd2963b518596e08a
Author: John Ralls <jralls at ceridwen.us>
Date:   Sun Jul 3 13:07:52 2022 -0700

    Fix use-after-free crash in utest-Invoice.



Summary of changes:
 libgnucash/engine/test/utest-Invoice.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)