Cookie Store API - Add tests for creation url, control characters, default secure

[RupinMittal]

Added tests:

1. Check that set/get/getAll are using the context's creation URL
2. Check that set fails if certain control characters are present in the name or value
3. Check that CookieListItem is secure by default (we want to test this property individually since the other tests in set_arguments check other properties first--so failing one of the earlier properties means we never check the secure property)

Changed tests:

1. There are two tests in set_arguments and delete_arguments that pass in the result of get() to delete(). These tests indirectly depend on the domain property. But Safari/Mozilla don't support domain being returned by get(). So we change these tests to not rely on domain. The test still passes for Chrome.