Add unit test for Phone Account sorting method.

Adds a unit test which verifies that the patch provided in b/207733460
is able to correct the issue with crashes when sorting PhoneAccounts
in CreateConnectionProcessor#sortSimPhoneAccountsForEmergency.

Test: Added new failing unit test to verify the patch provided in
b/207733460.
Bug: 207733460

Change-Id: I7fe488936995c243ee96cd492f841949172e144d