MDL-47617 behat: Fixed behat sorting failure

MDL-47617 behat: Fixed behat sorting failure

Postgres and MySQL treat values that are null differently
when sorting. MySQL will sort null values above fields with
values and Postgres will be vice versa. I removed the checks
against the Admin User.

Oracle treats lower case values different to upper case values
and so I have modified the test so that all Names start with
an Uppercase letter.