Spring CronTrigger uses new Date() instead of context's Clock

The nextExecutionTime(TriggerContext) method of CronTrigger uses new Date(); instead of using the specified context's clock. This makes it unnecessarily hard to unit test classes that create a trigger internally.

https://github.com/spring-projects/spring-framework/blob/276aa46a1c7c4bdd8ed23bd70e569334435ab4c7/spring-context/src/main/java/org/springframework/scheduling/support/CronTrigger.java#L108