Move blackBoxFile() testData to box/ directory

Delete all test methods (and empty test classes), since they'll be
auto-generated

compiler/testData/codegen/box/classes/delegationMethodsWithArgs.kt

@@ -0,0 +1,34 @@
+package test
+
+trait TextField {
+    fun getText(): String
+}
+
+trait InputTextField : TextField {
+    fun setText(text: String)
+}
+
+trait MooableTextField : InputTextField {
+    fun moo(a: Int, b: Int, c: Int): Int
+}
+
+class SimpleTextField : MooableTextField {
+    private var text = ""
+    override fun getText() = text
+    override fun setText(text: String) {
+        this.text = text
+    }
+    override fun moo(a: Int, b: Int, c: Int) = a + b + c
+}
+
+class TextFieldWrapper(textField: MooableTextField) : MooableTextField by textField
+
+fun box() : String {
+    val textField = TextFieldWrapper(SimpleTextField())
+    textField.setText("hello world!")
+
+    if (!textField.getText().equals("hello world!")) return "FAIL #!1"
+    if (textField.moo(1,2,3) != 6) return "FAIL #2"
+
+    return "OK"
+}