JS: report errors on different external items:

* data classes
* val/var parameters of primary constructors
* enum entry with body
* anonymous `init {}` block in classes

js/js.translator/testData/box/multiModuleWrappers/amd/jsModuleOnPackage.kt

@@ -4,7 +4,9 @@
 @file:JsModule("native-lib")
 package foo
 
-external class A(val x: Int = noImpl) {
+external class A(x: Int = noImpl) {
+    val x: Int
+
     fun foo(y: Int): Int = noImpl
 }