Rework S3Token middleware tests.

- Split between good and bad tests.
- Add more tests to get to 100% coverage.

Change-Id: Iffd00c2b557e54b122f29f8b0ec7f7ab7a92d16e
Imported Translations from Transifex

Change-Id: Iac5a165e7676afc20db9fff0059015938e6a7010
Merge "Rework S3Token middleware tests."