MemoryResourceProvider always uses the current platform

pkg/analyzer/test/source/analysis_options_provider_test.dart

Index: pkg/analyzer/test/source/analysis_options_provider_test.dart
diff --git a/pkg/analyzer/test/source/analysis_options_provider_test.dart b/pkg/analyzer/test/source/analysis_options_provider_test.dart
index adbadc706ec9fef5ce37533f1454b985856f948b..6e1b339a15feadd5117db506758292585481c3b0 100644
--- a/pkg/analyzer/test/source/analysis_options_provider_test.dart
+++ b/pkg/analyzer/test/source/analysis_options_provider_test.dart
@@ -120,7 +120,7 @@ abstract class AnalysisOptionsProviderTest {
   String get optionsFileName;
 
   void setUp() {
-    var rawProvider = new MemoryResourceProvider(isWindows: isWindows);
+    var rawProvider = new MemoryResourceProvider();
     resourceProvider = new TestResourceProvider(rawProvider);
     pathTranslator = new TestPathTranslator(rawProvider);
   }