- attempt to make `workingDirectory` test work on appVeyor - try to improve `runInShell` test
- attempt to make `workingDirectory` test work on appVeyor
- try to improve `runInShell` test

bwu-dart-contributing/grinder.dart,bwu-dart-contributing/grinder.dart,bwu-dart-contributing/grinder.dart,google/grinder.dart