AbstractDartSdk should not return its linked bundle if 'useSummary' is false.

pkg/analyzer/lib/src/dart/sdk/sdk.dart

Index: pkg/analyzer/lib/src/dart/sdk/sdk.dart
diff --git a/pkg/analyzer/lib/src/dart/sdk/sdk.dart b/pkg/analyzer/lib/src/dart/sdk/sdk.dart
index 0123bf8c1758f1a43514ee10cccb52cbba9f972e..7ab8272011ce21a18e8ded28635029be9e4f8fb7 100644
--- a/pkg/analyzer/lib/src/dart/sdk/sdk.dart
+++ b/pkg/analyzer/lib/src/dart/sdk/sdk.dart
@@ -155,9 +155,12 @@ abstract class AbstractDartSdk implements DartSdk {
 
   @override
   PackageBundle getLinkedBundle() {
-    bool strongMode = _analysisOptions?.strongMode ?? false;
-    _sdkBundle ??= getSummarySdkBundle(strongMode);
-    return _sdkBundle;
+    if (_useSummary) {
+      bool strongMode = _analysisOptions?.strongMode ?? false;
+      _sdkBundle ??= getSummarySdkBundle(strongMode);
+      return _sdkBundle;
+    }
+    return null;
   }
 
   String getRelativePathFromFile(File file);