Also test registration of standard coders.

[robertwb]

Noticed this while reviewing a PR.

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Post-Commit Tests Status (on master branch)

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

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.

[robertwb]

R: @ihji

[mxm]

Looks good. What was the PR? ;) I think I need to adapt my implementation here #8209 to support recursive coders.

[ihji]

+1

[robertwb]

#8205 (and also thinking about the StringUtf8 one).