RFR: 8268678: LetsEncryptCA.java test fails as Let’s Encrypt Authority X3 is retired

[Rajan Halade]

See the bug for more details.

- Intermediate root cert R3 doesn't specify OCSP responder and end entity test certificates doesn't specify CRLs
- New test artifacts are available but revoked expires on July 7th, 2021 and valid on August 31st, 2021. so backdated validity check is performed for OCSP.

If this fix is not acceptable for now then we can wait till CA updates test sites.

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Commit messages:
 - 8268678: LetsEncryptCA.java test fails as Let’s Encrypt Authority X3 is retired

Changes: https://git.openjdk.java.net/jdk/pull/4524/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4524&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8268678
  Stats: 125 lines in 1 file changed: 11 ins; 9 del; 105 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4524.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4524/head:pull/4524

PR: https://git.openjdk.java.net/jdk/pull/4524