[Tests] Migrate backend-independent tests from native to compiler/testData.

^KT-65979

compiler/testData/codegen/box/classDelegation/method.kt

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the LICENSE file.
+ */
+// WITH_STDLIB
+
+import kotlin.test.*
+
+interface A<T> {
+    fun foo(): T
+}
+
+class B : A<String> {
+    override fun foo() = "OK"
+}
+
+class C(a: A<String>) : A<String> by a
+
+fun box(): String {
+    val c = C(B())
+    val a: A<String> = c
+    val cfoo = c.foo()
+    if (cfoo != "OK") return "FAIL cfoo: $cfoo"
+    val afoo = a.foo()
+    if (afoo != "OK") return "FAIL afoo: $afoo"
+    return "OK"
+}