bitbake: methodpool: Clean up the parsed module list handling to be slightly less insane

This removes some dubious functions and replaces them with a simpler, cleaner
API which better describes what the code is doing. Unused code/variables are
removed and comments tweaked.

(Bitbake rev: f1e943aebfb84e98253f3f21646d6765c4fa1d66)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/parse/ast.py

@@ -31,7 +31,6 @@ import itertools
 from bb import methodpool
 from bb.parse import logger
 
-__parsed_methods__ = bb.methodpool.get_parsed_dict()
 _bbversions_re = re.compile(r"\[(?P<from>[0-9]+)-(?P<to>[0-9]+)\]")
 
 class StatementGroup(list):