Move some tests from boxWithStdlib/ to box/

Move those tests which do not require neither stdlib nor reflect

compiler/testData/codegen/box/dataClasses/equals/nullother.kt

@@ -0,0 +1,11 @@
+class Dummy {
+  override fun equals(other: Any?) = true
+}
+
+data class A(val v: Any?)
+
+fun box() : String {
+  val a = A(Dummy())
+  val b: A? = null
+  return if(a != b && b != a) "OK" else "fail"
+}