Remove throws from method that adopts assertThrows

[timtebeek]

What's your motivation?

• Fixes Removed unused checked exceptions, as discovered in JUnit 4 to 5 migration #563

[timtebeek]

Turns out we were overthinking this one; as we already replace the entire method body with assertThrows, there are then no exception left to be thrown that are not already caught.

[shivanisky]

I'm just thinking with the above, what if the method throws multiple checked exceptions, and assertThrows only catches one, even if it is wrapping the entire method body. I think in that case, the remaining checked exception are still valid, or still not? From my memory I remember only removing one checked exception from the method signature, and keeping one when doing the junit 4 to 5 migration, where there were multiple checked exceptions.