bisect: move 'printresult' in the 'hbisect' module
The logic is already extracted into a closure. We move it into the module
dedicated to bisect.
A minor change is applied: the creation of the 'displayer' is kept in the main
command function, it remove the needs to import 'cmdutil' in 'hbisect'. This
would create an import circle otherwise.
To run the tests, do:
cd tests/
python run-tests.py
See https://mercurial-scm.org/wiki/WritingTests for
more information on writing tests.