py3: for statprof's Chrome output, write json to string, then encode to bytes `json.dump(obj, fp)` requires `fp.write()` to accept str output, and since the file pointer we have there only accepts bytes, we need to change to json.dumps() and then encode as utf-8. We have already done the same thing for the json (non-Chrome) format in 4b7eb862692e (py3: encode json output to bytes and use write(), 2018-10-12). Differential Revision: https://phab.mercurial-scm.org/D6781

statprof: use context manager for file when writing flame graph Differential Revision: https://phab.mercurial-scm.org/D6780

statprof: use context manager when reading source from file Differential Revision: https://phab.mercurial-scm.org/D6779

statprof: clarify by naming tuple members while enumerate()'ing Differential Revision: https://phab.mercurial-scm.org/D6778

upgrade: make sure we reclone all revlogs when updating to some format Adding or removing some requirement (eg: sparserevlog), requires to reclone revlog to use the new format. We cannot simply copy the original files. In this case, we issue a warning to proceed with clone every revlogs.

upgrade: add an argument to control changelog upgrade Same as for `--manifest` we can now select more selection.

upgrade: add an argument to control manifest upgrade The argument can be used to only "clone" manifest revlog or clone all of them but this one. The selection will make more sense once we have a `--changelog` flag in the next changesets.

unionrepo: drop the custom `rawdata` implementation We can rely on the main one now.

unionrepo: drop `baserevdiff` It has no caller anymore.

unionrepo: use normal inheritance scheme to call revdiff

unionrepo: fix `revdiff` implementation to use `rawdata` The parent code is using rawdata so we should use it here. Before this change, union repo was probably broken with some flag processors.

unionrepo: get rid of `baserevision` The method is not called anywhere anymore, so we can safely drop it. Some of the comment get moved to `baserevdiff` because we did not got rid of it (yet).

unionrepo: use a lower level overide in unionrepo too The unionrepo class also have a strange `baserevision` hack, let's try to get ride of it too.

bundlerepo: drop the custom `rawdata` implementation We can rely on the main one now.

bundlerepo: drop the `baserevision` hack It is not used anywhere anymore, so we can safely drop it.