Merge branch 'mz/rebase-tests'

* mz/rebase-tests:
rebase topology tests: fix commit names on case-insensitive file systems
tests: move test for rebase messages from t3400 to t3406
t3406: modernize style
add tests for rebasing merged history
add tests for rebasing root
add tests for rebasing of empty commits
add tests for rebasing with patch-equivalence present
add simple tests of consistency across rebase types

diff --cc t/t3400-rebase.sh
Simple merge

diff --cc t/t3404-rebase-interactive.sh
Simple merge