t3201: test multiple branch filter combinations

t3201: test multiple branch filter combinations

Add tests covering the behavior of passing multiple contains/no-contains
filters to git branch, e.g.:

$ git branch --contains feature_a --contains feature_b
$ git branch --no-contains feature_a --no-contains feature_b

When passed more than one contains (or no-contains) filter, the tips of
the branches returned must be reachable from any of the contains commits
and from none of the the no-contains commits.

This logic is useful to describe prior to enabling multiple
merged/no-merged filters, so that future tests will demonstrate
consistent behavior between merged/no-merged and contains/no-contains
filters.

Signed-off-by: Aaron Lipman <alipman88@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>