Modernize account page tests
Review Request #9059 - Created July 7, 2017 and submitted
When adding the OAuth2 apps page, I neglected to update the account page
tests to account for the new page. While updating these tests, I
replaced the hardcoded strings of page IDs with fetching the default
page classes from the registry itself and updated all the tests to do
set comparisons instead of length comparisons, which did not indicate
why a test was failing, only that it was.
With this modernization, these tests shouldn't break in the future when
the set of pages changes.
Ran unit tests.