Stop using ExecutableElement.functions in tests.

pkg/analyzer/lib/src/generated/testing/node_search.dart

+// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/visitor.dart';
+
+/**
+ * Search the [unit] for declared [SimpleIdentifier]s with the given [name].
+ */
+List<SimpleIdentifier> findDeclaredIdentifiersByName(
+    CompilationUnit unit, String name) {
+  var finder = new _DeclaredIdentifiersByNameFinder(name);
+  unit.accept(finder);
+  return finder.identifiers;
+}
+
+class _DeclaredIdentifiersByNameFinder extends RecursiveAstVisitor<Null> {
+  final String name;
+  final List<SimpleIdentifier> identifiers = [];
+
+  _DeclaredIdentifiersByNameFinder(this.name);
+
+  @override
+  visitSimpleIdentifier(SimpleIdentifier node) {
+    if (node.name == name && node.inDeclarationContext()) {
+      identifiers.add(node);
+    }
+  }
+}