run-tests.py: pass -L/--label to simplemerge
This should give us conflict markers that don't change from one run
to another.
Remove some sed's/egrep's from some tests.
error: pretxncommit.nocommits hook failed: no commits allowed
abort: no commits allowed
transaction abort!
rollback completed
error: pretxncommit.nocommits hook failed: no commits allowed
abort: no commits allowed
transaction abort!
rollback completed