Fixing unit tests

[Validator] Fixing how default time zone is backed up during testing to not interfere with other tests
[HttpKernel] Fixing merge issue since 4677e92ffeac80

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |