Make async_bulk return also success results.

[bshakur8]

When stats_only is False, return a tuple of (results, errors), where results is the list of bulk results and errors is the current errors list.

[elasticmachine]

Since this is a community submitted pull request, a Jenkins build has not been kicked off automatically. Can an Elastic organization member please verify the contents of this patch and then kick off a build manually?

[cla-checker-service[bot]]

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