Apply ThreadLocal#remove() to pre-instantiation threads

See gh-13410
See gh-32874

Author: jhoeller

spring-beans/src/main/java/org/springframework/beans/factory/support/DefaultListableBeanFactory.java

@@ -1030,7 +1030,7 @@ public void preInstantiateSingletons() throws BeansException {
 			}
 		}
 		finally {
-			this.preInstantiationThread.set(null);
+			this.preInstantiationThread.remove();
 		}
 		if (!futures.isEmpty()) {
 			try {
@@ -1100,7 +1100,7 @@ private void instantiateSingletonInBackgroundThread(String beanName) {
 			throw ex;
 		}
 		finally {
-			this.preInstantiationThread.set(null);
+			this.preInstantiationThread.remove();
 		}
 	}