Tests to ensure the behavior of the specialized empty List, Set, Map implementations is same as of non-specialized ones.

libraries/stdlib/test/collections/CollectionJVMTest.kt

@@ -151,6 +151,7 @@ class CollectionJVMTest {
 
     test fun emptySetIsSerializable() = testSingletonSerialization(emptySet<Any>())
 
+    test fun emptyMapIsSerializable() = testSingletonSerialization(emptyMap<Any, Any>())
 
     private fun testSingletonSerialization(value: Any) {
         val outputStream = ByteArrayOutputStream()
@@ -168,3 +169,8 @@ class CollectionJVMTest {
         assertTrue(value === result)
     }
 }
+
+
+public fun assertTypeEquals(expected: Any?, actual: Any?) {
+    assertEquals(expected?.javaClass, actual?.javaClass)
+}