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/jsName/inheritFromRenamedNativeClass.kt

@@ -3,7 +3,9 @@
 package foo
 
 @JsName("A")
-external open class B(val foo: String)
+external open class B(foo: String) {
+    val foo: String
+}
 
 class C(s: String) : B(s)