Make Random implementations serializable (KT-25571)

Make Random.Default, XorWowRandom, and wrapper classes for JDK Random implement Serializable interface.

Co-authored-by: Ilya Gorbunov <ilya.gorbunov@jetbrains.com>

libraries/stdlib/src/kotlin/random/Random.kt

@@ -267,10 +267,17 @@ public abstract class Random {
      *
      * @sample samples.random.Randoms.defaultRandom
      */
-    companion object Default : Random() {
-
+    companion object Default : Random(), Serializable {
         private val defaultRandom: Random = defaultPlatformRandom()
 
+        private object Dummy : Serializable {
+            private const val serialVersionUID = 0L
+
+            private fun readResolve(): Any = Random
+        }
+
+        private fun writeReplace(): Any = Dummy
+
         override fun nextBits(bitCount: Int): Int = defaultRandom.nextBits(bitCount)
         override fun nextInt(): Int = defaultRandom.nextInt()
         override fun nextInt(until: Int): Int = defaultRandom.nextInt(until)
@@ -290,7 +297,8 @@ public abstract class Random {
 
         override fun nextBytes(array: ByteArray): ByteArray = defaultRandom.nextBytes(array)
         override fun nextBytes(size: Int): ByteArray = defaultRandom.nextBytes(size)
-        override fun nextBytes(array: ByteArray, fromIndex: Int, toIndex: Int): ByteArray = defaultRandom.nextBytes(array, fromIndex, toIndex)
+        override fun nextBytes(array: ByteArray, fromIndex: Int, toIndex: Int): ByteArray =
+            defaultRandom.nextBytes(array, fromIndex, toIndex)
     }
 }
 
@@ -325,7 +333,6 @@ public fun Random(seed: Int): Random = XorWowRandom(seed, seed.shr(31))
 public fun Random(seed: Long): Random = XorWowRandom(seed.toInt(), seed.shr(32).toInt())
 
 
-
 /**
  * Gets the next random `Int` from the random number generator in the specified [range].
  *

libraries/stdlib/src/kotlin/random/XorWowRandom.kt

@@ -15,15 +15,14 @@ package kotlin.random
  * Available at https://www.jstatsoft.org/v08/i14/paper
  *
  */
-internal class XorWowRandom
-internal constructor(
+internal class XorWowRandom internal constructor(
     private var x: Int,
     private var y: Int,
     private var z: Int,
     private var w: Int,
     private var v: Int,
     private var addend: Int
-) : Random() {
+) : Random(), Serializable {
 
     internal constructor(seed1: Int, seed2: Int) :
             this(seed1, seed2, 0, 0, seed1.inv(), (seed1 shl 10) xor (seed2 ushr 4))
@@ -53,4 +52,8 @@ internal constructor(
 
     override fun nextBits(bitCount: Int): Int =
         nextInt().takeUpperBits(bitCount)
+
+    private companion object {
+        private const val serialVersionUID: Long = 0L
+    }
 }