FIR: Serialize members originated from delegation

compiler/testData/codegen/box/delegation/delegationDifferentModule.kt

@@ -0,0 +1,16 @@
+// MODULE: lib
+// FILE: lib.kt
+interface A {
+    fun foo(): String
+}
+
+abstract class B(a: A) : A by a
+
+// MODULE: main(lib)
+// FILE: main.kt
+class AImpl : A {
+    override fun foo(): String = "OK"
+}
+class C : B(AImpl())
+
+fun box(): String = C().foo()