Correct abstract mutable collections declarations in kotlin-stdlib-common

Add SinceKotlin(1.3) to the new and substantially changed common declarations

#KT-28091

libraries/stdlib/js/src/kotlin/collections/AbstractMutableCollection.kt

@@ -10,11 +10,11 @@ package kotlin.collections
  *
  * @param E the type of elements contained in the collection. The collection is invariant on its element type.
  */
-public abstract class AbstractMutableCollection<E> protected constructor() : AbstractCollection<E>(), MutableCollection<E> {
+public actual abstract class AbstractMutableCollection<E> protected actual constructor() : AbstractCollection<E>(), MutableCollection<E> {
 
-    abstract override fun add(element: E): Boolean
+    actual abstract override fun add(element: E): Boolean
 
-    override fun remove(element: E): Boolean {
+    actual override fun remove(element: E): Boolean {
         val iterator = iterator()
         while (iterator.hasNext()) {
             if (iterator.next() == element) {
@@ -25,7 +25,7 @@ public abstract class AbstractMutableCollection<E> protected constructor() : Abs
         return false
     }
 
-    override fun addAll(elements: Collection<E>): Boolean {
+    actual override fun addAll(elements: Collection<E>): Boolean {
         var modified = false
         for (element in elements) {
             if (add(element)) modified = true
@@ -33,10 +33,10 @@ public abstract class AbstractMutableCollection<E> protected constructor() : Abs
         return modified
     }
 
-    override fun removeAll(elements: Collection<E>): Boolean = (this as MutableIterable<E>).removeAll { it in elements }
-    override fun retainAll(elements: Collection<E>): Boolean = (this as MutableIterable<E>).removeAll { it !in elements }
+    actual override fun removeAll(elements: Collection<E>): Boolean = (this as MutableIterable<E>).removeAll { it in elements }
+    actual override fun retainAll(elements: Collection<E>): Boolean = (this as MutableIterable<E>).removeAll { it !in elements }
 
-    override fun clear(): Unit {
+    actual override fun clear(): Unit {
         val iterator = this.iterator()
         while (iterator.hasNext()) {
             iterator.next()

libraries/stdlib/js/src/kotlin/collections/AbstractMutableMap.kt

@@ -41,12 +41,12 @@ public actual abstract class AbstractMutableMap<K, V> protected actual construct
 
     }
 
-    override fun clear() {
+    actual override fun clear() {
         entries.clear()
     }
 
     private var _keys: MutableSet<K>? = null
-    override val keys: MutableSet<K>
+    actual override val keys: MutableSet<K>
         get() {
             if (_keys == null) {
                 _keys = object : AbstractMutableSet<K>() {
@@ -82,14 +82,14 @@ public actual abstract class AbstractMutableMap<K, V> protected actual construct
 
     actual abstract override fun put(key: K, value: V): V?
 
-    override fun putAll(from: Map<out K, V>) {
+    actual override fun putAll(from: Map<out K, V>) {
         for ((key, value) in from) {
             put(key, value)
         }
     }
 
     private var _values: MutableCollection<V>? = null
-    override val values: MutableCollection<V>
+    actual override val values: MutableCollection<V>
         get() {
             if (_values == null) {
                 _values = object : AbstractMutableCollection<V>() {
@@ -122,10 +122,10 @@ public actual abstract class AbstractMutableMap<K, V> protected actual construct
             return _values!!
         }
 
-    override fun remove(key: K): V? {
+    actual override fun remove(key: K): V? {
         val iter = entries.iterator()
         while (iter.hasNext()) {
-            var entry = iter.next()
+            val entry = iter.next()
             val k = entry.key
             if (key == k) {
                 val value = entry.value