remotefilelog: include file contents in bundles produced during strip `hg strip` and other things that use repair.strip (such as the narrow extension's `hg tracked --removeinclude`) will "save" some commits that have a higher revision number than the oldest commit we're stripping, but aren't actually descended from any of the commits that we're stripping. It saves them in a bundle, and then reapplies them to the repo. Remotefilelog doesn't generally participate in strip, it doesn't contribute files to either the backup bundle or the "saved" bundle, and doesn't adjust linknodes when commits are stripped. This can break things like push, which rely on the linknodes. This change makes it so that remotefilelog includes files in these bundles during strip operations. During reapplication, the files are reapplied from the bundle, and the linknode is properly updated. Differential Revision: https://phab.mercurial-scm.org/D10320