RFR: 8295470: Update openjdk.java.net => openjdk.org URLs in test code

[Magnus Ihse Bursie]

This is a continuation of the effort to update all our URLs to the new top-level domain.

This patch updates (most) URLs in testing code. There still exists references to openjdk.java.net, but that are not strictly used as normal URLs, which I deemed need special care, so I left them out of this one, which is more of a straight-forward search and replace.

I have manually verified that the links work (or points to bugs.openjdk.org and looks sane; I did not click on all those). I have replaced `http` with `https`. I have replaced links to specific commits on the mercurial server with links to the corresponding commits in the new git repos.

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Commit messages:
 - 8295470: Update openjdk.java.net => openjdk.org URLs in test code

Changes: https://git.openjdk.org/jdk/pull/10744/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10744&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295470
  Stats: 138 lines in 45 files changed: 46 ins; 0 del; 92 mod
  Patch: https://git.openjdk.org/jdk/pull/10744.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10744/head:pull/10744

PR: https://git.openjdk.org/jdk/pull/10744