bundle2: lazily iterate over bundle parts in the test
We used to create a list to know the number of parts in the bundle. This prevents
any lazy reading as planned for real usage.
The list creation is dropped. Some test output changed as debug output is
now interleaved with command output.
To run the tests, do:
cd tests/
python run-tests.py
See http://mercurial.selenic.com/wiki/WritingTests for
more information on writing tests.