Optimize Handler::report

Summary:
Parent class method check the $dontReport array, then
log the exception.

As we have more logic, and this logic also require to
check what we want to report, we would check twice this
condition.

So we handle all the report logic in our class method,
without calling the parent class method anymore.

Test Plan:
Run tests.

A new test for an unreportable exception has been added.

Reviewers: dereckson

Subscribers: alken-orin

Maniphest Tasks: T765

Differential Revision: http://devcentral.nasqueron.org/D313