Add CRT HTTP/2 stability tests and JMH benchmarks

[zoewangg]

Motivation and Context

This PR adds stability tests and JMH benchmarks for the CRT HTTP client with HTTP/2 protocol support. These tests validate CRT HTTP/2 behavior under high-concurrency
scenarios using real AWS services (Kinesis and Transcribe Streaming) that support HTTP/2.

Modifications

New Stability Tests:

• KinesisCrtH2StabilityTest - Tests Kinesis SubscribeToShard streaming with CRT HTTP/2
• TranscribeStreamingCrtStabilityTest - Tests Transcribe Streaming bidirectional streaming with CRT HTTP/2

New JMH Benchmark:

• AwsCrtH2ClientBenchmark - Benchmarks CRT HTTP client with HTTP/2 over TLS

Refactoring:

• Created KinesisBaseStabilityTest to eliminate code duplication between Kinesis stability tests
• Created TranscribeStreamingBaseStabilityTest to eliminate code duplication between Transcribe Streaming stability tests

Benchmark Results (CRT HTTP/2 vs Netty HTTP/2):

Benchmark	CRT (ops/s)	Netty OpenSSL (ops/s)	Improvement
Concurrent	12,287 ± 433	7,156 ± 91	+72%
Sequential	3,760 ± 185	2,487 ± 54	+51%

Testing

• Stability tests require AWS credentials and create real Kinesis streams/Transcribe sessions
• JMH benchmarks run against local mock H2 server

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Checklist

• I have read the CONTRIBUTING document
• Local run of mvn install succeeds
• My code follows the code style of this project
• My change requires a change to the Javadoc documentation
• I have updated the Javadoc documentation accordingly
• I have added tests to cover my changes
• All new and existing tests pass
• I have added a changelog entry (N/A - test-only changes)

[sonarqubecloud]

Quality Gate failed

Failed conditions
62.1% Coverage on New Code (required ≥ 80%)
4.9% Duplication on New Code (required ≤ 3%)

See analysis details on SonarQube Cloud