Sycl implementation for objective functions (#9846)

---------

Co-authored-by: Dmitry Razdoburdin <>

tests/cpp/objective/test_multiclass_obj_cpu.cc

@@ -0,0 +1,25 @@
+/*!
+ * Copyright 2018-2023 XGBoost contributors
+ */
+#include <gtest/gtest.h>
+#include <xgboost/context.h>
+
+#include "../helpers.h"
+#include "test_multiclass_obj.h"
+
+namespace xgboost {
+TEST(Objective, DeclareUnifiedTest(SoftmaxMultiClassObjGPair)) {
+  Context ctx = MakeCUDACtx(GPUIDX);
+  TestSoftmaxMultiClassObjGPair(&ctx);
+}
+
+TEST(Objective, DeclareUnifiedTest(SoftmaxMultiClassBasic)) {
+  auto ctx = MakeCUDACtx(GPUIDX);
+  TestSoftmaxMultiClassBasic(&ctx);
+}
+
+TEST(Objective, DeclareUnifiedTest(SoftprobMultiClassBasic)) {
+  Context ctx = MakeCUDACtx(GPUIDX);
+  TestSoftprobMultiClassBasic(&ctx);
+}
+}  // namespace xgboost