[js-perf-test] Move SubRegExp class definition outside loop

test/js-perf-test/RegExp/base_ctor.js

Index: test/js-perf-test/RegExp/base_ctor.js
diff --git a/test/js-perf-test/RegExp/base_ctor.js b/test/js-perf-test/RegExp/base_ctor.js
index cacd43af59e45e7c2d3f159db5bca17d83c19dce..add4b6b6a3f8a4495b65b407a107654f2b878f60 100644
--- a/test/js-perf-test/RegExp/base_ctor.js
+++ b/test/js-perf-test/RegExp/base_ctor.js
@@ -26,11 +26,12 @@ function CtorWithRegExpPatternAndFlags() {
   new RegExp(/[Cz]/, "guiym");
 }
 
+class SubRegExp extends RegExp {
+  get source() { return "[Cz]"; }
+  get flags() { return "guiym"; }
+}
+
 function CtorWithRegExpSubclassPattern() {
-  class SubRegExp extends RegExp {
-    get source() { return "[Cz]"; }
-    get flags() { return "guiym"; }
-  }
   new RegExp(new SubRegExp(/[Cz]/));
 }