When running:
$ hg debugfileset 'binary() and ignored()'
getfileset() was correctly retrieving ignored files but
matchctx.existing() was not taking them in account. Just add them along
with unknown files.
By default, unknown files are ignored. If the 'unknown()' predicate
appears in the syntax tree, then they are taken in account.
Unfortunately, matchctx.existing() was filtering against non-deleted
context files, which does not include unknown files. So:
$ hg debugfileset 'binary() and unknown()'
would not return existing binary unknown files.
Running:
$ hg debugfileset 'binary()'
would traceback if there were one deleted file in the working directory.
It happened because matchctx.existing() was filtering files against the
ctx.__contains__() but deleted files are still considered part of
workingctx.
