Delete generated test cases, move testData to boxWithStdlib

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

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