[improve][misc] Upgrade jctools to 4.0.6 (jctools-core-jdk11)

[lhotari]

Motivation

The JCTools 4.0.6 release is available, with various fixes since 4.0.5. Keeping the dependency current is generally desirable.

Starting with 4.0.6, JCTools publishes a separate jctools-core-jdk11 Maven artifact that adds proper Java 9 module support (a module-info descriptor) on top of jctools-core. Switching to this artifact is the recommended way to consume JCTools on JDK 9+.

BookKeeper is also upgrading to JCTools 4.0.6 (apache/bookkeeper#4776), so aligning the version in Pulsar avoids classpath skew between the two projects and lets Pulsar pick up the jctools-core-jdk11 enhancements at the same time.

JCTools is used in Pulsar by managed-ledger and pulsar-transaction-coordinator.

Modifications

• Bump jctools version from 4.0.5 to 4.0.6 in gradle/libs.versions.toml.
• Add a jctools-core-jdk11 library entry to the version catalog alongside the existing jctools-core. Both share the same version.ref = "jctools" so they stay aligned.
• Switch the implementation declarations in managed-ledger and pulsar-transaction/coordinator from libs.jctools.core to libs.jctools.core.jdk11. The jdk11 variant transitively depends on jctools-core, so both jars end up bundled in the server distribution.
• Update distribution/server/src/assemble/LICENSE.bin.txt to list both org.jctools-jctools-core-4.0.6.jar and org.jctools-jctools-core-jdk11-4.0.6.jar.

Verified locally with:

./gradlew assemble
./src/check-binary-license.sh distribution/server/build/distributions/apache-pulsar-*-bin.tar.gz
./src/check-binary-license.sh distribution/shell/build/distributions/apache-pulsar-*-bin.tar.gz

(All exit 0; the shell distribution does not bundle jctools.)

Verifying this change

• Make sure that the change passes the CI checks.

This change is a trivial rework / code cleanup without any test coverage.

Does this pull request potentially affect one of the following parts:

• Dependencies (add or upgrade a dependency)
• The public API
• The schema
• The default values of configurations
• The threading model
• The binary protocol
• The REST endpoints
• The admin CLI options
• The metrics
• Anything that affects deployment

Dependency change details:

• org.jctools:jctools-core 4.0.5 → 4.0.6
• New direct dependency on org.jctools:jctools-core-jdk11 4.0.6 (replacing the previous direct jctools-core declaration; jctools-core itself is still bundled transitively through jctools-core-jdk11).

References

• Release notes: https://github.com/JCTools/JCTools/releases/tag/v4.0.6
• Changelog: JCTools/JCTools@v4.0.5...v4.0.6
• Related: Upgrade jctools to 4.0.6 (jctools-core-jdk11) bookkeeper#4776