[jdk8u-dev] RFR: 8318759: Add four DigiCert root certificates

[Severin Gehwolf]

Backport for adding 4 new digicert root certificates. Patch applies clean modulo path shuffeling.

Testing:
- [ ] GHA (still running)
- [x] jdk/test/security/infra/java/security/cert/CertPathValidator and jdk/test/sun/security/lib/cacerts jtreg tests. Including new ones. All 43 tests pass.

-------------

Depends on: https://git.openjdk.org/jdk8u-dev/pull/398

Commit messages:
 - Backport 0ea58048f9b4cdaaa0470b2bcc03913fb3939453

Changes: https://git.openjdk.org/jdk8u-dev/pull/399/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=399&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8318759
  Stats: 459 lines in 7 files changed: 456 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/399.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev.git pull/399/head:pull/399

PR: https://git.openjdk.org/jdk8u-dev/pull/399