Adds some more tests over equivalency's conversion step.
Adds some more tests over equivalency's conversion step.

dennisdoomen/fluentassertions,zmaruo/fluentassertions,ArsenShnurkov/fluentassertions,jeroenpot/FluentAssertions,vossad01/fluentassertions,AlexanderSher/fluentassertions,piotrpMSFT/fluentassertions,fluentassertions/fluentassertions,msackton/FluentAssertions,onovotny/fluentassertions,somewhatabstract/fluentassertions,rstam/fluentassertions,jnyrup/fluentassertions,dennisdoomen/fluentassertions,ben-m-lucas/FluentAssertions,levenleven/fluentassertions,MortenBoysen/FluentAssertions,jnyrup/fluentassertions,okobylianskyi/FluentAssertions,SaroTasciyan/FluentAssertions,fluentassertions/fluentassertions