Mark applicable Scope's methods as default

Signed-off-by: Yanming Zhou <zhouyanming@gmail.com>

spring-context/src/main/java/org/springframework/context/support/SimpleThreadScope.java

@@ -83,11 +83,6 @@ public class SimpleThreadScope implements Scope {
 				"Consider using RequestScope in a web environment.");
 	}
 
-	@Override
-	public @Nullable Object resolveContextualObject(String key) {
-		return null;
-	}
-
 	@Override
 	public String getConversationId() {
 		return Thread.currentThread().getName();