Fix driver_test.dart for Windows.

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 409802f1a7fa88a2d26d8f6071403404aad3daa5..7ce9f31aea1504e7cb54413f150f2ad8c7d477ae 100644
--- a/pkg/analyzer/test/src/dart/analysis/driver_test.dart
+++ b/pkg/analyzer/test/src/dart/analysis/driver_test.dart
@@ -320,8 +320,8 @@ var VC = new A<double>();
 
     {
       AnalysisResult result = await driver.getResult(c);
-      expect(_getImportSource(result.unit, 0).uri.toString(),
-          'file:///test/lib/a.dart');
+      expect(_getImportSource(result.unit, 0).uri,
+          provider.pathContext.toUri(_p('/test/lib/a.dart')));
       expect(_getTopLevelVarType(result.unit, 'VC'), 'A<double>');
     }
   }