RFR: 8325766: Review seclibs tests for cert expiry

[Matthew Donovan]

This PR updates the CertificateBuilder with a new method that creates a new 
instance with common fields (subject name, public key, serial number, validity, 
and key uses) filled-in. One test, IPIdentities.java, is updated to show how 
the method can be used to create various certificates. I attached screenshots 
that compare the old hard-coded certificates (left) with the new generated 
certificates.

![trusted-cert](https://github.com/user-attachments/assets/4bfaca10-74f3-4d24-9796-288358ae00e1)
![server-cert](https://github.com/user-attachments/assets/51ce8ed2-0784-44ab-96a1-9d0a2ea66aaa)
![client-cert](https://github.com/user-attachments/assets/5090a71e-ef7a-4303-ae1a-78f89878d1c0)

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Commit messages:
 - 8325766: Review seclibs tests for cert expiry

Changes: https://git.openjdk.org/jdk/pull/23700/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23700&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8325766
  Stats: 779 lines in 3 files changed: 154 ins; 599 del; 26 mod
  Patch: https://git.openjdk.org/jdk/pull/23700.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23700/head:pull/23700

PR: https://git.openjdk.org/jdk/pull/23700