Move blackBoxFile() testData to box/ directory

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

compiler/testData/codegen/box/properties/kt1170.kt

@@ -0,0 +1,16 @@
+public abstract class BaseClass() {
+    open val kind : String = "BaseClass "
+
+    fun getKindValue() : String {
+        return kind
+    }
+}
+
+public class Subclass : BaseClass() {
+    override val kind : String = "Subclass "
+}
+
+fun box(): String {
+    val r = Subclass().getKindValue() + Subclass().kind
+    return if(r == "Subclass Subclass ") "OK" else "fail"
+}