JVM_IR indy-lambdas: minor updates and fixes

KT-44278 KT-26060 KT-42621

compiler/testData/codegen/box/invokedynamic/lambdas/lambdaSerializable.kt

@@ -0,0 +1,13 @@
+// TARGET_BACKEND: JVM
+// IGNORE_BACKEND: JVM
+// JVM_TARGET: 1.8
+// LAMBDAS: INDY
+// FULL_JDK
+
+fun lambdaIsSerializable(fn: () -> Unit) = fn is java.io.Serializable
+
+fun box(): String {
+    if (lambdaIsSerializable {})
+        return "Failed: indy lambdas are not serializable"
+    return "OK"
+}