Use ThreadLocal.remove() instead of set(null)

Signed-off-by: Giheon Do <[email protected]>

See gh-46256

Author: Dockerel

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/SpringApplicationTests.java

@@ -167,6 +167,7 @@
  * @author Moritz Halbritter
  * @author Tadaya Tsuyukubo
  * @author Yanming Zhou
+ * @author Giheon Do
  */
 @ExtendWith(OutputCaptureExtension.class)
 class SpringApplicationTests {
@@ -1470,7 +1471,7 @@ void fromRunsWithAdditionalSources() {
 			.run()
 			.getApplicationContext();
 		assertThat(ExampleAdditionalConfig.local.get()).isNotNull();
-		ExampleAdditionalConfig.local.set(null);
+		ExampleAdditionalConfig.local.remove();
 	}
 
 	@Test