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

js/js.translator/testData/box/delegation/delegationByInh.kt

@@ -0,0 +1,47 @@
+package foo
+
+interface Base {
+    abstract fun foo(s: String): String
+    var prop: String
+}
+
+interface Base1 : Base {
+}
+
+interface Base2 : Base1 {
+    override fun foo(s: String): String = "Base2:foo ${s}"
+}
+
+class Base2Impl() : Base2 {
+    override var prop: String = ""
+        set(value) {
+            field = "prop:${value}"
+        }
+}
+
+class Derived() : Base by Base2Impl()
+
+class Derived1() : Base1 by Base2Impl()
+
+class Derived2() : Base2 by Base2Impl()
+
+fun box(): String {
+    assertEquals("Base2:foo !!", Derived().foo("!!"), "delegation (Base)")
+    assertEquals("Base2:foo !!", Derived1().foo("!!"), "delegation (Base1)")
+    assertEquals("Base2:foo !!", Derived2().foo("!!"), "delegation (Base2)")
+
+    var d = Derived()
+    d.prop = "A"
+    assertEquals("prop:A", d.prop, "delegation (Base) set property")
+
+    var d1 = Derived1()
+    d1.prop = "B"
+    assertEquals("prop:B", d1.prop, "delegation (Base1) set property")
+
+    var d2 = Derived1()
+    d2.prop = "C"
+    assertEquals("prop:C", d2.prop, "delegation (Base2) set property")
+
+    return "OK"
+}
+