Remove unused test code

[quapka]

While going through the test code, I've noticed that parts of the test code being unused. In particular, the a and expected variables. I grep'ed for all occurrences of the following lines in the test code and skimmed through the files for more unused code:

var a =
var b =
var expected =

C# not being my home turf, I did not manage to quickly get a static analysis run against the test code to find other cases and prevent this in the future.

This test in my branch 6.0 with netstandard2.0 failed first, but succeeded on a manual trigger - not sure how deterministic are the tests then.