Rewrite testTokenIsRemovedFromStorageWhenPersistentModeIsOff
Rewrite testTokenIsRemovedFromStorageWhenPersistentModeIsOff

When persistent mode is off, then the token should be removed from the
storage when it has been validated. This test did not do this, but does
do now.

slimphp/Slim-Csrf,akrabat/Slim-Csrf