Prohibit serializable annotation on local classes and anonymous objects

#KT-45541 Fixed

plugins/kotlin-serialization/kotlin-serialization-compiler/testData/diagnostics/LocalAndAnonymous.kt

@@ -0,0 +1,18 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER,-UNUSED_VARIABLE
+// WITH_RUNTIME
+// SKIP_TXT
+
+import kotlinx.serialization.*
+
+fun container() {
+    <!LOCAL_CLASSES_NOT_SUPPORTED!>@Serializable<!>
+    class X
+
+    val y = <!LOCAL_CLASSES_NOT_SUPPORTED!>@Serializable<!> object {}
+}
+
+val topLevelAnon = <!LOCAL_CLASSES_NOT_SUPPORTED!>@Serializable<!> object {}
+
+@Serializable class A {
+    @Serializable class B // nesting classes are allowed
+}