Issue 21662. Fix 'Sort Members' when both directives and declarations are updated.

pkg/analysis_server/test/services/correction/sort_members_test.dart

Index: pkg/analysis_server/test/services/correction/sort_members_test.dart
diff --git a/pkg/analysis_server/test/services/correction/sort_members_test.dart b/pkg/analysis_server/test/services/correction/sort_members_test.dart
index fe55eae93d76227e241805018b325993d8e679f4..1d0a975f22bfdcb50d48cee08279bbd07a3f1e1d 100644
--- a/pkg/analysis_server/test/services/correction/sort_members_test.dart
+++ b/pkg/analysis_server/test/services/correction/sort_members_test.dart
@@ -478,6 +478,29 @@ typedef FC();
 ''');
   }
 
+  void test_unitMembers_importsAndDeclarations() {
+    _parseTestUnit(r'''
+import 'dart:a';
+import 'package:b';
+
+main() {
+}
+
+f() => null;
+''');
+    // validate change
+    _assertSort(r'''
+import 'dart:a';
+
+import 'package:b';
+
+f() => null;
+
+main() {
+}
+''');
+  }
+
   void test_unitMembers_mix() {
     _parseTestUnit(r'''
 _mmm() {}