Remove deprecated code flagged for removal

Closes gh-27303

spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/ConfigFileApplicationContextInitializerTests.java

@@ -1,56 +0,0 @@
-/*
- * Copyright 2012-2021 the original author or authors.
- *
- * 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
- *
- *      https://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 org.springframework.boot.test.context;
-
-import org.junit.jupiter.api.Test;
-import org.junit.jupiter.api.extension.ExtendWith;
-
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.context.annotation.Configuration;
-import org.springframework.core.env.Environment;
-import org.springframework.test.annotation.DirtiesContext;
-import org.springframework.test.context.ContextConfiguration;
-import org.springframework.test.context.junit.jupiter.SpringExtension;
-
-import static org.assertj.core.api.Assertions.assertThat;
-
-/**
- * Tests for {@link ConfigFileApplicationContextInitializer}.
- *
- * @author Phillip Webb
- */
-@Deprecated
-@ExtendWith(SpringExtension.class)
-@DirtiesContext
-@ContextConfiguration(classes = ConfigFileApplicationContextInitializerTests.Config.class,
-		initializers = ConfigFileApplicationContextInitializer.class)
-class ConfigFileApplicationContextInitializerTests {
-
-	@Autowired
-	private Environment environment;
-
-	@Test
-	void initializerPopulatesEnvironment() {
-		assertThat(this.environment.getProperty("foo")).isEqualTo("bucket");
-	}
-
-	@Configuration(proxyBeanMethods = false)
-	static class Config {
-
-	}
-
-}