Fixes failing test due to sub-millisecond precision of Instant.now()

On some systems Instant.now() returns an Instant with sub-millisecond precision. The database tables this Instant is stored in only has millisecond precision, meaning the time fetched from the database is not the same as the time stored in the original Instant, causing tests to fail. This MR changes those cases to force Instants to a sane precision.