perf: if page_size or max_results is set on QueryJob.result(), use to download first page of results#1942

Linchin merged 8 commits into

maingoogleapis/python-bigquery:mainfrom

b344008814-page_size-query_and_waitgoogleapis/python-bigquery:b344008814-page_size-query_and_waitCopy head branch name to clipboard