largefiles: sync up `largefilesdirstate` methods with `dirstate` base class As it currently stands, pytype infers the `dirstate` class (and anything else decorated with `@interfaceutil.implementer`) as `Any`. When that is worked around, it suddenly noticed that most of these methods don't exist in the `dirstate` class anymore. Since they only called into the missing methods and there's no test failures, we can assume these are never called, and they can be dropped. In addition, PyCharm flagged `set_tracked()` and `_ignore()` as not overriding a superclass method with the same arguments. The missing default parameter for the former was the obvious issue. I'm guessing that the latter was named wrong because while there is `_ignore()` in the base class, it takes no arguments and returns a matcher. The `_ignorefiles()` superclass method also takes no args, and returns a list of bytes. The `_ignorefileandline()` superclass method DOES take a file, but returns a tuple. Therefore, the closest match is `_dirignore()`, which takes a file AND returns a bool. No idea why this needs to be overridden though.