Fix CLI SDK option config timing (#26129).

pkg/analyzer_cli/test/driver_test.dart

Index: pkg/analyzer_cli/test/driver_test.dart
diff --git a/pkg/analyzer_cli/test/driver_test.dart b/pkg/analyzer_cli/test/driver_test.dart
index 0b48331a7ca2029facd65516bbde2f89453e1d56..6c858801a03b7f5ae8876f7697d1d72237cb174e 100644
--- a/pkg/analyzer_cli/test/driver_test.dart
+++ b/pkg/analyzer_cli/test/driver_test.dart
@@ -263,6 +263,15 @@ linter:
           doDrive();
           expect(driver.context.analysisOptions.enableSuperMixins, isTrue);
         });
+
+        test('strongMode', () {
+          doDrive();
+          expect(driver.context.analysisOptions.strongMode, isTrue);
+          //https://github.com/dart-lang/sdk/issues/26129
+          AnalysisContext sdkContext =
+              driver.context.sourceFactory.dartSdk.context;
+          expect(sdkContext.analysisOptions.strongMode, isTrue);
+        });
       });
 
       group('with flags', () {