Earlier there was a single backend test for testing group edit policy
for creating and deleting user group.This commit make changes in the test
and now there are two separate tests for testing group edit policy for
creating and deleting user groups.
This was done because in future commits we will be adding a
realm level setting for configuring who can create user groups.
Also, updated tests to use api_post and api_delete helpers instead
of using client_post and client_delete helpers with different users
being logged in.
9e699dfc85