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

js/js.translator/testData/box/defaultArguments/enumSuperConstructor.kt

@@ -0,0 +1,16 @@
+package foo
+
+enum class A {
+    B(2);
+
+    val c: Int
+
+    constructor (a: Int, b: Int = 3) {
+        c = a + b
+    }
+}
+
+fun box(): String {
+    assertEquals(5, A.B.c)
+    return "OK"
+}