rebase: add a stateobj variable to rebaseruntime class
The stateobj variable is an object of state.cmdstate() and will be used in
upcoming patches to clean up the logic a bit and also use cbor format to write
data to rebasestate class.
Differential Revision: https://phab.mercurial-scm.org/D3874
cat >> $HGRCPATH <<EOF
[extensions]
narrow=
[ui]
ssh=python "$TESTDIR/dummyssh"
[experimental]
changegroup3 = True
EOF