[BEAM-8387] Remove sdk-worker-parallelism option from JobServerDriver

[tweise]

This option was added when it wasn't possible to specify the worker count as pipeline option, which is no longer the case. The pipeline option has a special value of 0, which means that the runner should pick a suitable value. Unfortunately this was overridden in FlinkJobInvoker with 1 (because that's the default in the JobServerDriver config). There is no need to have this option in the job server.

---

Thank you for your contribution! Follow this checklist to help us incorporate your contribution quickly and easily:

• Choose reviewer(s) and mention them in a comment (R: @username).
• Format the pull request title like [BEAM-XXX] Fixes bug in ApproximateQuantiles, where you replace BEAM-XXX with the appropriate JIRA issue, if applicable. This will automatically link the pull request to the issue.
• If this contribution is large, please file an Apache Individual Contributor License Agreement.

Post-Commit Tests Status (on master branch)

Lang	SDK	Apex	Dataflow	Flink	Gearpump	Samza	Spark
Go		---	---		---	---
Java
Python		---			---	---
XLang	---	---	---		---	---	---

Pre-Commit Tests Status (on master branch)

---	Java	Python	Go	Website
Non-portable
Portable	---		---	---

See .test-infra/jenkins/README for trigger phrase, status and link of all Jenkins jobs.

[mxm]

Good catch. I agree that the option is not needed in the JobServerDriver..

[ibzib]

LGTM, I always thought having the same argument set in both places added unnecessary complexity (like BEAM-7657).