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/kt2477.kt

@@ -0,0 +1,22 @@
+package test
+
+trait A {
+    public val c: String
+        get() = "OK"
+}
+
+trait B {
+    protected val c: String
+}
+
+open class C {
+    private val c: String = "FAIL"
+}
+
+open class D: C(), A, B {
+    val b = c
+}
+
+fun box() : String {
+    return D().c
+}