Always return computed errors, even for not added files.

pkg/analyzer/test/src/dart/analysis/driver_test.dart

Index: pkg/analyzer/test/src/dart/analysis/driver_test.dart
diff --git a/pkg/analyzer/test/src/dart/analysis/driver_test.dart b/pkg/analyzer/test/src/dart/analysis/driver_test.dart
index 7bd4dcec793f05dacf52c28ee11f55b33fe7ca3a..79e551fb2d420bb234117154b3c4e7f60f5d5fbd 100644
--- a/pkg/analyzer/test/src/dart/analysis/driver_test.dart
+++ b/pkg/analyzer/test/src/dart/analysis/driver_test.dart
@@ -1317,14 +1317,6 @@ var V;
     await driver.getResult(testFile);
   }
 
-  test_getResult_noErrors_ifNotAdded() async {
-    var a = _p('/test/lib/a.dart');
-    provider.newFile(a, 'A a = null;');
-
-    AnalysisResult result = await driver.getResult(a);
-    expect(result.errors, isEmpty);
-  }
-
   test_getResult_notDartFile() async {
     var path = _p('/test/lib/test.txt');
     provider.newFile(path, 'class A {}');