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

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

Index: test/js-perf-test/PropertyQueries/property-queries.js
diff --git a/test/js-perf-test/PropertyQueries/property-queries.js b/test/js-perf-test/PropertyQueries/property-queries.js
index f763d262d4ebec8a97072070d078b5f24163156a..06146c752a42087c4a21b9c57eda66f0511c13a7 100644
--- a/test/js-perf-test/PropertyQueries/property-queries.js
+++ b/test/js-perf-test/PropertyQueries/property-queries.js
@@ -71,7 +71,10 @@ function IntArray(size) {
 // 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;
 }