Support KType.javaType in stdlib

#KT-32241 Fixed

libraries/stdlib/jvm/runtime/kotlin/jvm/internal/KTypeBase.kt

@@ -0,0 +1,14 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package kotlin.jvm.internal
+
+import java.lang.reflect.Type
+import kotlin.reflect.KType
+
+@SinceKotlin("1.4")
+public interface KTypeBase : KType {
+    val javaType: Type?
+}