* add dotnet format tests
* some updates from code review
* move helper methods out of DotNetFormatTests class
* rearrange smoke test assets
* update various smoke-test paths and remove root repo check from legacy smoke test script
* fix smoke-test-prereqs tar command path
* fix naming conventions and remove extra formatting test
* more refactoring from pr comments
* refactor BaselineHelper comparison methods
* simplify comparison methods
* clarify FormatTest expected result naming
* remove unnecessary empty props and targets files
