[js-perf-tests] Fix PropertyQueries test for fast-delete

test/js-perf-test/PropertyQueries/property-queries.js

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 function ObjectWithKeys(count, keyOffset = 0, keyGen) {
   var body = "";
   for (var i = 0; i < count; i++) {
     var key = keyGen(i + keyOffset);
     if (typeof key === "string") {
       body += `this.${key} = 0\n`;
@@ skipping 53 matching lines @@
   var array = new Array(size);
   for (var i = 0; i < size; i++) {
     array[i] = i;
   }
   return array;
 }
 
 // Switch object's properties and elements to dictionary mode.
 function MakeDictionaryMode(obj) {
   obj.foo = 0;
+  obj.bar = 0;
+  // Delete the second-to-last property first to force normalization.
   delete obj.foo;
+  delete obj.bar;
   obj[1e9] = 0;
   return obj;
 }
 
 function Internalize(s) {
   return Object.keys({[s]:0})[0];
 }
 
 function Deinternalize(s) {
   return [...s].join("");
@@ skipping 180 matching lines @@
       }
       var run_function = CombineTestFunctions(tests);
       var benchmark = new Benchmark(name, false, false, 0, run_function);
       benchmarks.push(benchmark);
     }
     Benchmarks.push(new BenchmarkSuite(suit_name, [100], benchmarks));
   }
 }
 
 // ============================================================================