[jdk21u] RFR: 8295068: SSLEngine throws NPE parsing CertificateRequests

[Aleksey Shipilev]

Clean backport to handle the SSL corner case.

Additional testing:
 - [x] macos-aarch64-server-fastdebug, `jdk_security`

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Commit messages:
 - Backport 5667afc36275b064c7700518f453fe8657e13636

Changes: https://git.openjdk.org/jdk21u/pull/257/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk21u&pr=257&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295068
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk21u/pull/257.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u.git pull/257/head:pull/257

PR: https://git.openjdk.org/jdk21u/pull/257