RFR: 958: Add test cases for known corner cases for synclabel bot [v2]

[Robin Westberg]

> Add special exclude list, proper BPR detection for 9+, and tests.

Robin Westberg has updated the pull request incrementally with one additional commit since the last revision:

  Adjust config tests to not use known ignored version 8u4x

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Changes:
  - all: https://git.openjdk.java.net/skara/pull/1109/files
  - new: https://git.openjdk.java.net/skara/pull/1109/files/77302fa8..71cc0fab

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=skara&pr=1109&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=skara&pr=1109&range=00-01

  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/skara/pull/1109.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1109/head:pull/1109

PR: https://git.openjdk.java.net/skara/pull/1109