[jdk8u-dev] RFR: 8339560: Unaddressed comments during code review of JDK-8337664

[Severin Gehwolf]

I'm backporting this test-only refactoring so that future distrust changes are easier to apply. In particular, this backport eases backporting [JDK-8346587](https://bugs.openjdk.org/browse/JDK-8346587). The patch was mostly done by hand as it didn't apply cleanly.

Notable changes:
- `/test/lib` => `/lib/security` test library changes
- Manual renames of cert chains due to changed paths in JDK 8u
- Applied hunks manually to Distrust.java (rename from `Entrust/Distrust.java` as well).

Testing:
- [x] Tests in `sun/security/ssl/X509TrustManagerImpl`

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Commit messages:
 - 8339560: Unaddressed comments during code review of JDK-8337664

Changes: https://git.openjdk.org/jdk8u-dev/pull/626/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=626&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8339560
  Stats: 924 lines in 26 files changed: 389 ins; 535 del; 0 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/626.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev.git pull/626/head:pull/626

PR: https://git.openjdk.org/jdk8u-dev/pull/626