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

js/js.translator/testData/box/enum/enumInheritedFromTrait.kt

@@ -0,0 +1,16 @@
+package foo
+
+fun box() = MyEnum.E1.f() + MyEnum.E2.f()
+
+enum class MyEnum : T {
+    E1 {
+        override fun f() = "O"
+    },
+    E2 {
+        override fun f() = "K"
+    }
+}
+
+interface T {
+    fun f(): String
+}