By deferring the evaluation of these messages, we can avoid the
expensive creation of them when in the majority use case (tests are
passing) they are not needed.
These failure messages were causing performance problems with larger
objects needed to be pretty printed as discussed in #520 and brought up
by @rdy.
[fixes#65925900][fixes#520]
- Passing in a 'negativeCompare' will cause that function to be used when it is a 'not' assertion
- Otherwise, the reversal of the compare's result will be used instead
[finishes #59703824]
