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/native/passExtLambdaToNative.kt

@@ -1,6 +1,8 @@
 package foo
 
-external class A(val v: String)
+external class A(v: String) {
+    val v: String
+}
 
 external fun bar(a: A, extLambda: A.(Int, String) -> String): String = noImpl