[SPARK-12972][CORE] Update org.apache.httpcomponents.httpclient

## What changes were proposed in this pull request?

(Retry of https://github.com/apache/spark/pull/13049)

- update to httpclient 4.5 / httpcore 4.4
- remove some defunct exclusions
- manage httpmime version to match
- update selenium / httpunit to support 4.5 (possible now that Jetty 9 is used)

## How was this patch tested?

Jenkins tests. Also, locally running the same test command of one Jenkins profile that failed: `mvn -Phadoop-2.6 -Pyarn -Phive -Phive-thriftserver -Pkinesis-asl ...`

Author: Sean Owen <sowen@cloudera.com>

Closes #13117 from srowen/SPARK-12972.2.