Delete generated test cases, move testData to boxWithStdlib

compiler/testData/codegen/boxWithStdlib/dataClasses/equals/instanceof.kt

@@ -0,0 +1,13 @@
+class Dummy {
+  fun equals(other: Any?) = true
+}
+
+open data class A(val v: Any)
+
+class B(v: Any) : A(v)
+
+fun box() : String {
+  val a = A(Dummy())
+  val b = B(Dummy())
+  return if(b == a) "OK" else "fail"
+}