Delete generated test cases, move testData to boxWithStdlib

compiler/testData/codegen/boxWithStdlib/dataClasses/copy/copyInObjectNestedDataClass.kt

@@ -0,0 +1,15 @@
+class Bar(val name: String)
+
+abstract class Foo {
+  public abstract fun foo(): String
+}
+
+fun box(): String {
+    return object: Foo() {
+      inner data class NestedFoo(val bar: Bar)
+
+      override fun foo(): String {
+        return NestedFoo(Bar("Fail")).copy(bar = Bar("OK")).bar.name
+      }
+    }.foo()
+}