Separate actions and conflict attributes.

* bzrlib/tests/test_conflicts.py:
(TestParametrizedResolveConflicts): Separate actions from
additional info needed to check the conflict objects, since this
is specific to daughter classes, this is delegated. Reorder the
dicts used to define the scenarios.
(TestParametrizedResolveConflicts.scenarios): Document the
scenario structure.
(TestParametrizedResolveConflicts.setUp): Extract just the actions
from the relevant attributes.
(TestResolveContentsConflict, TestResolvePathConflict,
TestResolveDuplicateEntry, TestResolveParentLoop): Implement the
specific conflict attributes handling. And simplify the helpers
accordingly.
(TestResolvePathConflictBefore531967.assertPathConflict): Grrr,
redo the fix lost in the merge from trunk.