[js-perf-test] Add microbenchmarks for leaf constructors.

Bug: v8:6679
Change-Id: I1fff8ffa037629636f31ecd2b731f5b9de89ce44
Reviewed-on: https://chromium-review.googlesource.com/604789Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47209}

test/js-perf-test/Classes/leaf-constructors.js

+// Copyright 2017 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.
+'use strict';
+
+var DefaultConstructorBenchmark = new BenchmarkSuite('LeafConstructors',
+    [100], [
+      new Benchmark('WithExplicitArguments', false, false, 0,
+                    WithExplicitArguments),
+    ]);
+
+
+const Point = class Point {
+  constructor(x, y, z) { this.x = x; this.y = y; this.z = z; }
+}
+
+const klasses = [
+  class A extends Point { constructor(x, y, z) { super(x, y, z); } },
+  class B extends Point { constructor(x, y, z) { super(x, y, z); } },
+  class C extends Point { constructor(x, y, z) { super(x, y, z); } },
+  class D extends Point { constructor(x, y, z) { super(x, y, z); } },
+  class E extends Point { constructor(x, y, z) { super(x, y, z); } }
+];
+
+function WithExplicitArguments() {
+  let result = null;
+  for (const klass of klasses) {
+    result = new klass(0, 1, 2);
+  }
+  return result;
+};

test/js-perf-test/Classes/run.js

@@ -6,6 +6,7 @@
 load('../base.js');
 load('super.js');
 load('default-constructor.js');
+load('leaf-constructors.js');
 
 
 var success = true;

test/js-perf-test/JSTests.json

@@ -84,11 +84,15 @@
       "name": "Classes",
       "path": ["Classes"],
       "main": "run.js",
-      "resources": ["super.js", "default-constructor.js"],
+      "resources": [
+        "super.js",
+        "default-constructor.js",
+        "leaf-constructors.js"],
       "results_regexp": "^%s\\-Classes\\(Score\\): (.+)$",
       "tests": [
         {"name": "Super"},
-        {"name": "DefaultConstructor"}
+        {"name": "DefaultConstructor"},
+        {"name": "LeafConstructors"}
       ]
     },
     {