Remove mock for Time::now() after test completion
Remove mock for Time::now() after test completion

so that other tests that expect Time::now() not to be mocked,
like PrivateMessageTest::testSend_limitExceeded(), do not fail.

Tatoeba/tatoeba2,Tatoeba/tatoeba2,Tatoeba/tatoeba2,Tatoeba/tatoeba2,Tatoeba/tatoeba2