SpringBoot Remove TomcatEmbeddedContext.overrideLoadOnStart

I think we can remove the overrideLoadOnStart reflection hacks in TomcatEmbeddedContext now since we no longer support older versions of Tomcat.

Comment From: Proximator

I am using spring-boot1 and I would like to set this option to false to do some experiments, is that possible? thanks

Comment From: philwebb

@Proximator, Spring Boot 1.x has reached end of life. Please upgrade to Spring Boot 2.6.