RFR: 1448: Support specialized suffix pool records for legacy releases

[Erik Joelsson]

This patch makes it possible to define specialized "pool" versions with suffixes for 8u in JBS, similar to how it's already possible for 11u+. For example: we could create a JBS `8-pool-foo` version that got consumed by commits with fixVersion `8u331-foo`.

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

Commit messages:
 - SKARA-1448

Changes: https://git.openjdk.java.net/skara/pull/1320/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=1320&range=00
  Issue: https://bugs.openjdk.java.net/browse/SKARA-1448
  Stats: 18 lines in 3 files changed: 16 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/skara/pull/1320.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1320/head:pull/1320

PR: https://git.openjdk.java.net/skara/pull/1320