rebase: avoid clobbering wdir() with --dry-run or --confirm (issue6291) See 56d3e0b499df for the source of adding originalwd to the list of things that cause wdir to be updated. That change didn't come with tests, and attempts to recreate the scenario described have thus far failed. Differential Revision: https://phab.mercurial-scm.org/D8489

tests: show that rebase --dry-run and --confirm wipeout uncommitted changes It looks like the carnage is limited to rebasing something that is not an ancestor of wdir(), as both of these abort in a preflight check for that case with a dirty working directory. Differential Revision: https://phab.mercurial-scm.org/D8488

Added signature for changeset 065704cbdbdb

Added tag 5.4.1 for changeset 065704cbdbdb

py3: update comment to account for Python 2 and Python 3 differences

py3: add warning about buffering behavior of pycompat.{stdout,stderr}