Allow AbstractEnvironment to bypass active/default properties

[philwebb]

See spring-projects/spring-boot#24890 (comment) for more background.

Currently AbstractEnvironment has doGetActiveProfiles() and doGetDefaultProfiles() methods that will call getProperty() if there aren't any set values. In Spring Boot we call setActiveProfiles(..) and setDefaultProfiles(...) directly and we don't want property based resolution (even if the values set are an empty array).

We'd like a way to disable property based resolution.

[philwebb]

I pushed a suggested implementation here