Enhancements to webform user test coverage.

Adding better test coverage to webform user. These tests cover
the most critical features of webform user including:

1. Reading user entity fields and creating the correct webform components.
2. Respect for entity field display options such as hidden.
3. Ensure invalid field types like field are ignored.
4. Anonymous form submissions (both matching and non-matching emails).
5. Authenticated user form repopulation and submission.
6. Values saved correctly to user account object.
7. New user email option.

There is a non-functioning test for confirmation page tokens that isn't
currently doing anything. Perhaps there should be no tokens since it
only works with authenticated user.
Merge branch '7.x-4x-webform_user_test_updates' into 7.x-4.x