RFR: 8272875: Change the default key manager to PKIX

[Artur Barashev]

The current key manager is SunX509, which is configured in the java.security. The SunX509 algorithm does not check of the local certificate. The PKIX algorithm should be preferred now so that the default key manager could be more robust.

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Commit messages:
 - Rework unit tests
 - Use standard PKIX alias
 - Merge branch 'master' into JDK-8272875
 - 8272875: Change the default key manager to PKIX

Changes: https://git.openjdk.org/jdk/pull/24756/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24756&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8272875
  Stats: 213 lines in 10 files changed: 158 ins; 25 del; 30 mod
  Patch: https://git.openjdk.org/jdk/pull/24756.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24756/head:pull/24756

PR: https://git.openjdk.org/jdk/pull/24756