(PUP-798) Add call to watch_files to ensure reparsing

This adds a call to watch_file in the code path for the future
parser/evaluator at the same place such call is made in the 3x
implementation. 

The ParserFactory is given an environment, and when this is 
a real environment, its known_resource_types are given to the parser
adapter being created to allow it to make the call to watch_file.