RFR: 1340: Correct email domain not always used when adding a contributor to a PR [v3]

[Zhao Song]

> Now, the email domain for additional contributors is always the default "openjdk.org" domain because we hardcoded it.
> 
> To resolve this issue, we should use the domain in jcheck configuration file.

Zhao Song has updated the pull request incrementally with one additional commit since the last revision:

  add a test

-------------

Changes:
  - all: https://git.openjdk.org/skara/pull/1513/files
  - new: https://git.openjdk.org/skara/pull/1513/files/b2bc9c37..bf623cfa

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=skara&pr=1513&range=02
 - incr: https://webrevs.openjdk.org/?repo=skara&pr=1513&range=01-02

  Stats: 92 lines in 1 file changed: 92 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/skara/pull/1513.diff
  Fetch: git fetch https://git.openjdk.org/skara.git pull/1513/head:pull/1513

PR: https://git.openjdk.org/skara/pull/1513