Fix serialVersionUID for EmptyMap and EmptySet

Otherwise removal of redundant special stubs
leads to InvalidClassException during deserialization

libraries/stdlib/src/kotlin/collections/Maps.kt

@@ -7,6 +7,8 @@ import java.io.Serializable
 import java.util.*
 
 private object EmptyMap : Map<Any?, Nothing>, Serializable {
+    private const val serialVersionUID: Long = 8246714829545688274
+
     override fun equals(other: Any?): Boolean = other is Map<*,*> && other.isEmpty()
     override fun hashCode(): Int = 0
     override fun toString(): String = "{}"

libraries/stdlib/src/kotlin/collections/Sets.kt

@@ -8,6 +8,8 @@ import java.util.*
 
 
 internal object EmptySet : Set<Nothing>, Serializable {
+    private const val serialVersionUID: Long = 3406603774387020532
+
     override fun equals(other: Any?): Boolean = other is Set<*> && other.isEmpty()
     override fun hashCode(): Int = 0
     override fun toString(): String = "[]"
@@ -80,4 +82,4 @@ internal fun <T> Set<T>.optimizeReadOnlySet() = when (size) {
     0 -> emptySet()
     1 -> setOf(iterator().next())
     else -> this
-}
+}