fix: correctly iterate query results within stream

[stephenplusplus]

Fixes #303

In a stream, we-- y'know what, @oliverwoodings explained it best: #303 (comment)

• My code calls bigquery.createQueryStream() with a query. Note that this function has been wrapped by @google-cloud/paginator
• This calls queryAsStream_ (https://github.com/googleapis/nodejs-bigquery/blob/master/src/index.ts#L1515), which ends up calling createQueryJob
• After we have a job, we call job.getQueryResults (https://github.com/googleapis/nodejs-bigquery/blob/master/src/index.ts#L1505).
• After getting the job status, the job i'm running hasn't completed, so we call back with no rows and no page token (https://github.com/googleapis/nodejs-bigquery/blob/master/src/job.ts#L418-L428)
• The callback given to getQueryResults that is called at this point is actually the results handler from @google-cloud/paginator (https://github.com/googleapis/nodejs-paginator/blob/master/src/index.ts#L315)
• Because there is a nextQuery given to onResultSet of the paginator, and there are still rows to send, the paginator executes the request again (https://github.com/googleapis/nodejs-paginator/blob/master/src/index.ts#L332-L335)
• makeRequest in the paginator calls originalMethod, which in this case is actually BigQuery.queryAsStream_, which means it tries to create an entire new query job, instead of just polling for more results?!

[oliverwoodings]

Woo! Thanks for the amazingly fast fix. Glad you were able to follow my code diving :)

[stephenplusplus]

@oliverwoodings it's your patience going through all of that that is most impressive :D