Remove workaround for LOG4J2-3618

Closes gh-41906

Author: wilkinsona

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/logging/log4j2/Log4J2LoggingSystemTests.java

@@ -24,7 +24,6 @@
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
 import java.util.logging.Handler;
 import java.util.logging.Level;
 
@@ -43,7 +42,6 @@
 import org.apache.logging.log4j.core.util.ShutdownCallbackRegistry;
 import org.apache.logging.log4j.jul.Log4jBridgeHandler;
 import org.apache.logging.log4j.util.PropertiesUtil;
-import org.apache.logging.log4j.util.PropertySource;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -64,7 +62,6 @@
 import org.springframework.boot.testsupport.system.OutputCaptureExtension;
 import org.springframework.core.env.Environment;
 import org.springframework.mock.env.MockEnvironment;
-import org.springframework.test.util.ReflectionTestUtils;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.StringUtils;
 
@@ -110,7 +107,6 @@ void setup() {
 		this.configuration = loggerContext.getConfiguration();
 		this.loggingSystem.cleanUp();
 		this.logger = LogManager.getLogger(getClass());
-		cleanUpPropertySources();
 	}
 
 	@AfterEach
@@ -119,19 +115,9 @@ void cleanUp() {
 		LoggerContext loggerContext = (LoggerContext) LogManager.getContext(false);
 		loggerContext.stop();
 		loggerContext.start(((Reconfigurable) this.configuration).reconfigure());
-		cleanUpPropertySources();
 		PluginRegistry.getInstance().clear();
 	}
 
-	@SuppressWarnings("unchecked")
-	private void cleanUpPropertySources() { // https://issues.apache.org/jira/browse/LOG4J2-3618
-		PropertiesUtil properties = PropertiesUtil.getProperties();
-		Object environment = ReflectionTestUtils.getField(properties, "environment");
-		Set<PropertySource> sources = (Set<PropertySource>) ReflectionTestUtils.getField(environment, "sources");
-		sources.removeIf((candidate) -> candidate instanceof SpringEnvironmentPropertySource
-				|| candidate instanceof SpringBootPropertySource);
-	}
-
 	@Test
 	void noFile(CapturedOutput output) {
 		this.loggingSystem.beforeInitialize();