After we upgraded to QUnit 1.23.1, we gained support for
assert.expect(). This allows us to guard against any race conditions
within tests, because now expect() will be linked to the specific test
instead of the current running test.
This adds the test that ensures that the search focus is still
focused, even after the selection is updated (for whatever reason).
Note that we are not triggering the `change` event here, and are
instead just re-calling `update` on the selection adapter. This is
because we do not bind the `change` event in tests, so the selection
is never re-rendered and the tests will pass. The `update` method
is triggered during the `change` cycle anyway, so this has the
same effect while supporting cases where the selection is re-rendered
without the selected values changing.
