Check that min epoch < max epoch in PhabricatorFeedQuery::withEpochInRange()

Summary:
PhabricatorFeedQuery::withEpochInRange() returns zero results when passing parameters in the wrong order.
Instead return a PhutilArgumentUsageException which makes it clear why there are no results.

Test Plan:
On an early morning without coffee supply, write custom code like

$query = id(new PhabricatorFeedQuery())
         ->setViewer(PhabricatorUser::getOmnipotentUser())
         ->withFilterPHIDs(array($user->getPHID()))
         ->withEpochInRange(time(), time() - 86400)
         ->setReturnPartialResultsOnOverheat(true);
$stories = $query->execute();

and wonder why you get zero results. Optionally, feel stupid for a moment.
Apply patch, now get an "Unhandled Exception ("PhutilArgumentUsageException") - Minimum range must be lower than maximum range."

Reviewers: O1 Blessed Committers, valerio.bozzolan

Reviewed By: O1 Blessed Committers, valerio.bozzolan

Subscribers: tobiaswiese, valerio.bozzolan, Matthew, Cigaryno

Differential Revision: https://we.phorge.it/D25891