Fix #28120, strong mode allows field overrides

pkg/dev_compiler/test/codegen_expected/BenchmarkBase.js

Index: pkg/dev_compiler/test/codegen_expected/BenchmarkBase.js
diff --git a/pkg/dev_compiler/test/codegen_expected/BenchmarkBase.js b/pkg/dev_compiler/test/codegen_expected/BenchmarkBase.js
index 803a049d772766da0e1b3b8416c9025bf42ca0b9..ce511defea2eb68be93708af558f118192342ac0 100644
--- a/pkg/dev_compiler/test/codegen_expected/BenchmarkBase.js
+++ b/pkg/dev_compiler/test/codegen_expected/BenchmarkBase.js
@@ -32,8 +32,14 @@ define(['dart_sdk'], function(dart_sdk) {
     names: ['equals', 'listEquals']
   });
   BenchmarkBase$.BenchmarkBase = class BenchmarkBase extends core.Object {
+    get name() {
+      return this[name$];
+    }
+    set name(value) {
+      super.name = value;
+    }
     new(name) {
-      this.name = name;
+      this[name$] = name;
     }
     run() {}
     warmup() {
@@ -75,6 +81,7 @@ define(['dart_sdk'], function(dart_sdk) {
       core.print(dart.str`${this.name}(RunTime): ${score} us.`);
     }
   };
+  const name$ = Symbol("BenchmarkBase.name");
   dart.setSignature(BenchmarkBase$.BenchmarkBase, {
     fields: () => ({name: core.String}),
     methods: () => ({