JS: create new common directory for all generated tests, migrate several tests there

js/js.translator/testData/box/inheritance/baseClassDefinedAfterDerived.kt

@@ -0,0 +1,13 @@
+package foo
+
+
+class A() : B() {
+
+}
+
+open class B() {
+
+    val a = 3
+}
+
+fun box() = if (A().a == 3) "OK" else "fail"