Don't load Object as a supertype for Java classes

#KT-4890 In Progress
 #KT-5002 Fixed

compiler/testData/codegen/boxWithStdlib/dataClasses/kt5002.kt

@@ -0,0 +1,15 @@
+import java.io.Serializable
+
+public data class Pair<out A, out B> (
+        public val first: A,
+        public val second: B
+) : Serializable
+
+fun box(): String {
+    val p = Pair(42, "OK")
+    val q = Pair(42, "OK")
+    if (p != q) return "Fail equals"
+    if (p.hashCode() != q.hashCode()) return "Fail hashCode"
+    if (p.toString() != q.toString()) return "Fail toString"
+    return p.second
+}