rebase: add dryrun property to rebaseruntime
I want to be able to check the property in
`rebaseruntime._rebasenode()`. Passing the value via the runtime is a
convenient way.
Differential Revision: https://phab.mercurial-scm.org/D9074
To run the tests, do:
cd tests/
python run-tests.py
See https://mercurial-scm.org/wiki/WritingTests for
more information on writing tests.