Result shall take failed assumptions also into account

[Reissner]

In some version assumptions came into the game
but tests with failed assumtions do not go into Results: in fact they cannot be distinghished from passed tests which i think is inadequate.
Suggestion: add a category besides ignored: invalidated holding tests with failed assumptions.
The number of those is the number of invocations of testAssumtionFailure..

[marcphilipp]

There's already a pull request for that: #1294.