RFR: 8257617: TestLinkPlatform fails with new Java source version

[Hannes Wallnöfer]

This fixes the problem that some tests in TestLinkPlatform.java rely on a static list of properties, causing them to fail when a new Java source version is added. The solution is to create the properties file on the fly. 

I also replaced the custom documentation domain with "example.com" as suggested in the original PR.

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

Commit messages:
 - JDK-8257617: TestLinkPlatform fails with new Java source version

Changes: https://git.openjdk.java.net/jdk/pull/1588/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1588&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8257617
  Stats: 28 lines in 2 files changed: 13 ins; 10 del; 5 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1588.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1588/head:pull/1588

PR: https://git.openjdk.java.net/jdk/pull/1588