gnucash maint: Add more tests for neutral time.

[John Ralls]

Updated	 via  https://github.com/Gnucash/gnucash/commit/8b616449 (commit)
	from  https://github.com/Gnucash/gnucash/commit/6d9e7d93 (commit)



commit 8b6164497852737f85e4246746db8953a4860107
Author: John Ralls <jralls at ceridwen.us>
Date:   Sat Mar 14 10:15:12 2020 -0700

    Add more tests for neutral time.



Summary of changes:
 libgnucash/engine/test/gtest-gnc-datetime.cpp | 42 ++++++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)