Merge boxWithStdlib testData into box, delete BoxWithStdlib test

compiler/testData/codegen/box/reflection/mapping/mappedClassIsEqualToClassLiteral.kt

@@ -0,0 +1,14 @@
+// WITH_REFLECT
+
+class A
+
+fun box(): String {
+    val a1 = A::class.java.kotlin
+    val a2 = A::class
+
+    if (a1 != a2) return "Fail equals"
+    if (a1.hashCode() != a2.hashCode()) return "Fail hashCode"
+    if (a1.toString() != a2.toString()) return "Fail toString"
+
+    return "OK"
+}