Allow DirectoryDescriptor.load to load a file next to a directory.

pkg/scheduled_test/test/descriptor/nothing_test.dart

Index: pkg/scheduled_test/test/descriptor/nothing_test.dart
diff --git a/pkg/scheduled_test/test/descriptor/nothing_test.dart b/pkg/scheduled_test/test/descriptor/nothing_test.dart
index 902fc4e8a4a1dfdc790086fa2af0e7731ff50188..0e623341cf489d8aeb14061096e2e97f18212fea 100644
--- a/pkg/scheduled_test/test/descriptor/nothing_test.dart
+++ b/pkg/scheduled_test/test/descriptor/nothing_test.dart
@@ -84,22 +84,4 @@ void main() {
               r"directory\.$"));
     });
   }, passing: ['test 2']);
-
-  expectTestsPass("nothing().load() fails", () {
-    test('test', () {
-      scheduleSandbox();
-
-      expect(d.nothing('name.txt').load('path').toList(),
-          throwsA(equals("Nothing descriptors don't support load().")));
-    });
-  });
-
-  expectTestsPass("nothing().read() fails", () {
-    test('test', () {
-      scheduleSandbox();
-
-      expect(d.nothing('name.txt').read().toList(),
-          throwsA(equals("Nothing descriptors don't support read().")));
-    });
-  });
 }