log_replay_iter and scan_action_iter need to know the table root so they canonicalize add/remove paths

[nicklan]

It's not required that a Remove action that removes a particular file has the exact same path as the Add action that added it, as long as they resolve to the same thing.

For example you could:

1. Add a file with path: "/path/to/file"
2. Remove it with path: "file:/path/to/file

Since these are canonically both file:///path/to/file, the remove should remove the file.

We therefore (I think), need to pass the table root down into these methods so they can canonicalize against the root (this would be different if the table was in S3 since the Add file would canonicalize to s3:///path/to/file).

In general absolute paths in add/remove actions seems like a bad idea, but it's allowed by the PROTOCOL, so we should support it.