Null-terminate Collection.toArray destination only in JVM

In other platforms the elements following the collection elements
should not be changed.

As a part of efforts to stabilize Native stdlib.

libraries/stdlib/wasm/src/kotlin/collections/ArraysWasm.kt

@@ -34,8 +34,5 @@ internal actual fun <T> copyToArrayImpl(collection: Collection<*>, array: Array<
     while (iterator.hasNext()) {
         array[index++] = iterator.next() as T
     }
-    if (index < array.size) {
-        (array as Array<T?>).fill(null, index)
-    }
-    return array
+    return terminateCollectionToArray(collection.size, array)
 }