totalBytesProcessed is not exposed from RowIterator

[bnaul]

RowIterator resulting from query_and_wait() for the new short query mode exposes most of its internal state via properties (cf. e.g. num_dml_affected_rows) but does not provide a total_bytes_processed property to access self.totalBytesProcessed. It would be nice if as many as possible of the same attributes were present to make transitioning to query_and_wait() from query() as smooth as possible.

I'm sure there are other attributes too but this is the one that I ran into first.

[tswast]

totalBytesProcessed is exposed by the jobs.query response body, so this should be feasible. There's a few other stats exposed on that message, but not all that many.