Suppress code warnings in kotlin-stdlib

core/builtins/native/kotlin/Collections.kt

@@ -328,7 +328,7 @@ public interface Map<K, out V> {
     @PlatformDependent
     public fun getOrDefault(key: K, defaultValue: @UnsafeVariance V): V {
         // See default implementation in JDK sources
-        return null as V
+        throw NotImplementedError()
     }
 
     // Views