[Math] implement Math.random as TFJ builtin.

src/js/math.js

-// Copyright 2012 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(global, utils) {
-"use strict";
-
-%CheckIsBootstrapping();
-
-// -------------------------------------------------------------------
-// Imports
-
-// The first two slots are reserved to persist PRNG state.
-define kRandomNumberStart = 2;
-
-var GlobalMath = global.Math;
-var NaN = %GetRootNaN();
-var nextRandomIndex = 0;
-var randomNumbers = UNDEFINED;
-var toStringTagSymbol = utils.ImportNow("to_string_tag_symbol");
-
-//-------------------------------------------------------------------
-// ECMA 262 - 15.8.2.14
-function MathRandom() {
-  // While creating a startup snapshot, %GenerateRandomNumbers returns a
-  // normal array containing a single random number, and has to be called for
-  // every new random number.
-  // Otherwise, it returns a pre-populated typed array of random numbers. The
-  // first two elements are reserved for the PRNG state.
-  if (nextRandomIndex <= kRandomNumberStart) {
-    randomNumbers = %GenerateRandomNumbers(randomNumbers);
-    if (%_IsTypedArray(randomNumbers)) {
-      nextRandomIndex = %_TypedArrayGetLength(randomNumbers);
-    } else {
-      nextRandomIndex = randomNumbers.length;
-    }
-  }
-  return randomNumbers[--nextRandomIndex];
-}
-
-// -------------------------------------------------------------------
-
-%AddNamedProperty(GlobalMath, toStringTagSymbol, "Math", READ_ONLY | DONT_ENUM);
-
-// Set up non-enumerable functions of the Math object and
-// set their names.
-utils.InstallFunctions(GlobalMath, DONT_ENUM, [
-  "random", MathRandom,
-]);
-
-%SetForceInlineFlag(MathRandom);
-
-// -------------------------------------------------------------------
-// Exports
-
-utils.Export(function(to) {
-  to.MathRandom = MathRandom;
-});
-
-})