Update environment handling in "AotSpringBootConfigContextLoader"

[ttddyy]

These commits in Boot (by @philwebb) impact the Environment handlings in AotSpringBootConfigContextLoader.

• Allow test property sources to override command line args spring-projects/spring-boot#29404
• Change SpringBootContextLoader.getEnvironment to return null by default spring-projects/spring-boot#29405
• clean up commit: spring-projects/spring-boot@9c48195

[snicoll]

These are both in Spring Boot 2.7.x and Spring Native builds against Spring Boot 2.6.x. If we decide to switch to 2.7.x at some point, we will have to review all the overrides that we have anyway so I am not sure what to do here.

[sdeleuze]

Thanks for your feedback @ttddyy, closing this one since no immediate actionable item and no milestone created for a Spring Boot 2.7 baseline yet so we will do an extensive review when we will upgrade as pointed out by @snicoll.