Bugfix: Update unit tests and fix problems exposed after fixing unit tests for f_netw...

Bugfix: Update unit tests and fix problems exposed after fixing unit tests for f_network_is_ip_address().

This is a follow up to these commits:
- 0e69871e03990990e0ebdf1b496ece67c40f4b5e
- 309f2625e983ef164c52543b492365fe92eed6d5

Add additional tests.
Fix bad test data, such as where the string lengths are incorrect.
Perform tests when "where" parameter both is NULL or is a valid pointer.
The tests now handle validating the "where" parameter, when specified.

Add additional comments to better communicate the logic in f_network_is_ip_address().
Properly handle the "where" parameter assignment.