RFR: 8243559: Remove root certificates with 1024-bit keys

[Sean Mullan]

This change removes five root certificates with 1024-bit RSA public keys from the system-wide `cacerts` keystore. These are older VeriSign and Thawte root CA certificates which are no longer necessary to retain and should have minimal compatibility risk if removed.

See the CSR for more details: https://bugs.openjdk.java.net/browse/JDK-8256502

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Commit messages:
 - 8256502: Remove root certificates with 1024-bit keys

Changes: https://git.openjdk.java.net/jdk/pull/1387/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1387&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8243559
  Stats: 140 lines in 6 files changed: 0 ins; 138 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1387.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1387/head:pull/1387

PR: https://git.openjdk.java.net/jdk/pull/1387