JS: move more test to box tests

js/js.translator/testData/box/objectDeclaration/kt3684.kt

@@ -0,0 +1,18 @@
+// copied from JVM backend tests
+package foo
+
+open class X(private val n: String) {
+
+    fun foo(): String {
+        return object : X("inner") {
+            fun print(): String {
+                return n;
+            }
+        }.print()
+    }
+}
+
+
+fun box(): String {
+  return X("OK").foo()
+}