Revert "Skip Token tests if user doesn't have rights"

As TokenWallet.__getitem__ has side effects and caches the
token if needed, a 'in' only checks if the token has been
cached (see also the docstring of TokenWallet.__contains__).

A test done before merging this has been able to execute
'test_token'
( https://travis-ci.org/wikimedia/pywikibot-core/jobs/45416313#L801 )
while a test with this merged in has skipped it
( https://travis-ci.org/wikimedia/pywikibot-core/jobs/45420743#L800 ).

This reverts commit affc77a480653aba1631b3c38cc5376390730579.

Change-Id: Ia229b6473b075dd3e8a17a48f9d054d0ec0977bc
Merge "Revert "Skip Token tests if user doesn't have rights""