AjLookupEnvironment: readability refactoring

While trying to understand the code a bit better in order to fix failing
builds, I applied some cosmetic refactoring and reformatting. This
commit does not change any functionality.

Whether the static import of CompilationAndWeavingContext.* is a good
thing or not is debatable, but I like the code to be less chatty than it
was before, assuming that every developer uses an IDE helping to find
out where static methods and constants come from.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>