feat(profiling): Reference-count RecordingData lifecycle

[jbachorik]

What Does This Do

Adds retain and release reference counting to RecordingData.

• RecordingData gains retain() and release() next to close(). The recording stream stays open until the last consumer releases its reference.
• The OpenJDK, OracleJDK, and ddprof controller backends implement the new contract.
• RecordingDataRefCountingTest covers the behavior.

Motivation

The profiling controller hands a RecordingData to a listener, and close() ends the recording. One consumer model exists today. The OTLP profiles uploader needs a second consumer of the same recording. It must read the JFR data and send it as OTLP/P while the streaming path still reads it.

With the current API the two consumers conflict. The first close() can end the recording while the uploader still reads it. The upload then sends an incomplete profile. The uploader can also hold the recording open after both consumers finish. The recording then leaks, and its file grows.

Retain and release reference counting solves both cases. Each consumer holds a reference. The recording closes only after the last consumer releases its reference.

This PR changes only the RecordingData contract and its backend implementations. The uploader that uses it comes in a later PR of the stack.

Additional Notes

Part of a 5-PR stack. Each PR bases on the previous one.

1. The payload and request body move (refactor: Move OtlpPayload and OTLP request bodies to communication/otlp-exporter #12880)
2. The sender extraction and the canonical resource attributes (refactor: Extract OTLP sender infrastructure to communication/otlp-exporter #12868)
3. this PR: RecordingData reference counting
4. JFR to OTLP/P converter, profiling-otel, plus jafar 0.26.2 (feat(profiling): Add JFR to OTLP/P converter with CLI, benchmarks and validation #12870)
5. OTLP profiles export wiring (feat(profiling): Integrate OTLP profiles export into the agent #12871)

Contributor Checklist

• Format the title according to the contribution guidelines
• Assign the type: and (comp: or inst:) labels in addition to any other useful labels
• Update the CODEOWNERS file on source file addition, migration, or deletion
• Update public documentation with any new configuration flags or behaviors
• Once approved, use merge queue to merge the PR

Jira ticket: [PROJ-IDENT]