[jvm-package] Clean up the legacy gpu support tests (#7523)

jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/GpuTestSuite.java

@@ -1,28 +0,0 @@
-/*
- Copyright (c) 2020 by Contributors
-
- Licensed under the Apache License, Version 2.0 (the "License");
- you may not use this file except in compliance with the License.
- You may obtain a copy of the License at
-
- http://www.apache.org/licenses/LICENSE-2.0
-
- Unless required by applicable law or agreed to in writing, software
- distributed under the License is distributed on an "AS IS" BASIS,
- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- See the License for the specific language governing permissions and
- limitations under the License.
- */
-package ml.dmlc.xgboost4j.java;
-
-import java.lang.annotation.ElementType;
-import java.lang.annotation.Retention;
-import java.lang.annotation.RetentionPolicy;
-import java.lang.annotation.Target;
-
-import org.scalatest.TagAnnotation;
-
-@TagAnnotation
-@Retention(RetentionPolicy.RUNTIME)
-@Target({ElementType.METHOD, ElementType.TYPE})
-public @interface GpuTestSuite {}