JVM_IR: serialize anonymous functions' descriptors

compiler/testData/codegen/box/reflection/lambdaClasses/parameterNamesAndNullability.kt

@@ -1,5 +1,4 @@
 // IGNORE_BACKEND_FIR: JVM_IR
-// IGNORE_BACKEND: JVM_IR
 // TARGET_BACKEND: JVM
 
 // WITH_REFLECT

compiler/testData/codegen/box/reflection/lambdaClasses/reflectOnLambdaInField.kt

@@ -0,0 +1,13 @@
+// IGNORE_BACKEND_FIR: JVM_IR
+// TARGET_BACKEND: JVM
+// WITH_REFLECT
+
+import kotlin.reflect.jvm.reflect
+
+class C {
+    val x = { OK: String -> }
+}
+
+fun box(): String {
+    return C().x.reflect()?.parameters?.singleOrNull()?.name ?: "null"
+}

compiler/testData/codegen/box/reflection/lambdaClasses/reflectOnLambdaInStaticField.kt

@@ -0,0 +1,12 @@
+// IGNORE_BACKEND_FIR: JVM_IR
+// IGNORE_BACKEND: JVM_IR
+// TARGET_BACKEND: JVM
+// WITH_REFLECT
+
+import kotlin.reflect.jvm.reflect
+
+val x = { OK: String -> }
+
+fun box(): String {
+    return x.reflect()?.parameters?.singleOrNull()?.name ?: "null"
+}