fileset: make debugfileset filter repository files This prepares for the structural change of the fileset. A computed fileset will no longer be a set of files, but a boolean function (i.e. matcher) to test if an input file matches the given fileset expression. --all-files option is added because some examples in the test need to scan files across revisions.

--- a/tests/test-fileset.t	Sun Jul 08 19:24:18 2018 +0900
+++ b/tests/test-fileset.t	Sat Jun 09 18:58:16 2018 +0900
@@ -1,5 +1,5 @@
   $ fileset() {
-  >   hg debugfileset "$@"
+  >   hg debugfileset --all-files "$@"
   > }
 
   $ hg init repo