Don't remove nullability assertions of anonymous object transformation

#KT-19910 Fixed

compiler/testData/codegen/boxAgainstJava/inline/kt19910.kt

@@ -0,0 +1,39 @@
+// FILE: J.java
+// FULL_JDK
+// WITH_RUNTIME
+// TARGET_BACKEND: JVM
+public class J {
+    public interface Consumer {
+        void accept(String p);
+    }
+
+    public static void invokeWithNull(Consumer x) {
+        x.accept(null);
+    }
+}
+
+// FILE: Kotlin.kt
+
+
+inline fun makeRunnable(crossinline lambda: () -> Unit) =
+        object : Runnable {
+            override fun run() {
+                lambda()
+            }
+        }
+
+fun box(): String {
+    try {
+        makeRunnable {
+            J.invokeWithNull(object : J.Consumer {
+                override fun accept(t: String) {
+                    println(t)
+                }
+            })
+        }.run()
+    } catch (e: IllegalArgumentException) {
+        return "OK"
+    }
+
+    return "fail: exception expected"
+}