reverted back to path instead of pathos and use explicit package root, just like buildbot

pkg/docgen/test/single_library_test.dart

Index: pkg/docgen/test/single_library_test.dart
diff --git a/pkg/docgen/test/single_library_test.dart b/pkg/docgen/test/single_library_test.dart
index e92c8571ac47bdef85076dd3356732d6cdab7f71..f00ddc4d2f40f6fd14723f493208212aae702fa4 100644
--- a/pkg/docgen/test/single_library_test.dart
+++ b/pkg/docgen/test/single_library_test.dart
@@ -57,8 +57,12 @@ main() {
           var classes = library.classes.values;
           expect(classes.every((e) => e is Class), isTrue);
           
+          var classMethodTypes = [];
+          classes.forEach((e) => classMethodTypes.addAll(e.methods.values));
+          expect(classMethodTypes.every((e) => e is Map), isTrue);
+
           var classMethods = [];
-          classes.forEach((e) => classMethods.addAll(e.methods.values));
+          classMethodTypes.forEach((e) => classMethods.addAll(e.values));
           expect(classMethods.every((e) => e is Method), isTrue);
           
           var methodParameters = [];
@@ -67,7 +71,11 @@ main() {
           });
           expect(methodParameters.every((e) => e is Parameter), isTrue);
           
-          var functions = library.functions.values;
+          var functionTypes = library.functions.values;
+          expect(functionTypes.every((e) => e is Map), isTrue);
+          
+          var functions = [];
+          functionTypes.forEach((e) => functions.addAll(e.values));
           expect(functions.every((e) => e is Method), isTrue);
           
           var functionParameters = [];