KT-54739 Return single empty instance from collection builders on JVM

- return single instance of emptySet for build method from SetBuilder
- return single instance of emptyMap for build method from MapBuilder
- return single instance of emptyList for build method from ListBuilder

^KT-54739 fixed

libraries/stdlib/jvm/src/kotlin/collections/builders/ListBuilder.kt

@@ -17,6 +17,9 @@ internal class ListBuilder<E> private constructor(
     private val backing: ListBuilder<E>?,
     private val root: ListBuilder<E>?
 ) : MutableList<E>, RandomAccess, AbstractMutableList<E>(), Serializable {
+    private companion object {
+        private val Empty = ListBuilder<Nothing>(0).also { it.isReadOnly = true }
+    }
 
     constructor() : this(10)
 
@@ -27,7 +30,7 @@ internal class ListBuilder<E> private constructor(
         if (backing != null) throw IllegalStateException() // just in case somebody casts subList to ListBuilder
         checkIsMutable()
         isReadOnly = true
-        return this
+        return if (length > 0) this else Empty
     }
 
     private fun writeReplace(): Any =

libraries/stdlib/jvm/src/kotlin/collections/builders/MapBuilder.kt

@@ -50,7 +50,8 @@ internal class MapBuilder<K, V> private constructor(
     fun build(): Map<K, V> {
         checkIsMutable()
         isReadOnly = true
-        return this
+        @Suppress("UNCHECKED_CAST")
+        return if (size > 0) this else (Empty as Map<K, V>)
     }
 
     private fun writeReplace(): Any =
@@ -459,12 +460,14 @@ internal class MapBuilder<K, V> private constructor(
     internal fun valuesIterator() = ValuesItr(this)
     internal fun entriesIterator() = EntriesItr(this)
 
-    private companion object {
+    internal companion object {
         private const val MAGIC = -1640531527 // 2654435769L.toInt(), golden ratio
         private const val INITIAL_CAPACITY = 8
         private const val INITIAL_MAX_PROBE_DISTANCE = 2
         private const val TOMBSTONE = -1
 
+        internal val Empty = MapBuilder<Nothing, Nothing>(0).also { it.isReadOnly = true }
+
         private fun computeHashSize(capacity: Int): Int = (capacity.coerceAtLeast(1) * 3).takeHighestOneBit()
 
         private fun computeShift(hashSize: Int): Int = hashSize.countLeadingZeroBits() + 1

libraries/stdlib/jvm/src/kotlin/collections/builders/SetBuilder.kt

@@ -10,6 +10,9 @@ import java.io.NotSerializableException
 internal class SetBuilder<E> internal constructor(
     private val backing: MapBuilder<E, *>
 ) : MutableSet<E>, AbstractMutableSet<E>(), Serializable {
+    private companion object {
+        private val Empty = SetBuilder(MapBuilder.Empty)
+    }
 
     constructor() : this(MapBuilder<E, Nothing>())
 
@@ -17,7 +20,7 @@ internal class SetBuilder<E> internal constructor(
 
     fun build(): Set<E> {
         backing.build()
-        return this
+        return if (size > 0) this else Empty
     }
 
     private fun writeReplace(): Any =