Allow when creating a Transaction() use PatchedCursor

[ecarreras]

For now if we want to patch the creation of new cursors inside a test we have to do:

with Transaction().start(self.database) as txn:
    with PatchNewCursors():
        ...

Maybe we can add the possibillity in creation a new Transaction to define to use PatchedCursors as

with Transaction(same_cursor=True).start(self.database) as txn:
    ...