Refactor consistency proof tests (#2180)
Refactor consistency proof tests (#2180)

* Make variable names short
* Specify struct field names
* Run nested tests using t.Run
* Use cmp package to compare slices
* Remove unnecessary helper
* Move global constants to the test scope
* Leave one example instead of many diagrams
* Inline constants
* Reorder according to size1
* Add more tests
* Remove reference to RFC from the comment
google/trillian,AlCutter/trillian,AlCutter/trillian,google/trillian