Fix netty instrumentation requirement for JDK 27

[sarahchen6]

What Does This Do

Loosen netty instrumentation error check

Motivation

JDK 27 changes the socket connection-refused message from:

Connection refused: /127.0.0.1:61

to:

Connection refused (connect failed): /127.0.0.1:61

Additional Notes

Full GitLab pipeline that runs non-default JVMs, JDK 27 tests included: https://gitlab.ddbuild.io/DataDog/apm-reliability/dd-trace-java/-/pipelines/123869235

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
• Avoid using close, fix, or any linking keywords when referencing an issue
  Use solves instead, and assign the PR milestone to the issue
• 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]

[dd-octo-sts]

🟢 Java Benchmark SLOs — All performance SLOs passed

Suite	Status
Startup	🟢 pass

SLO thresholds are defined here based on automatically generated metrics. A warning is raised when results are within 5% of the threshold.

PR vs. master results

Scenario	Candidate	master	Δ (95% CI of mean)
startup:insecure-bank:iast:Agent	13.98 s	13.94 s	[-0.5%; +1.1%] (no difference)
startup:insecure-bank:tracing:Agent	12.94 s	12.98 s	[-1.0%; +0.4%] (no difference)
startup:petclinic:appsec:Agent	17.46 s	17.25 s	[+0.1%; +2.3%] (maybe worse)
startup:petclinic:iast:Agent	17.42 s	17.50 s	[-1.4%; +0.5%] (no difference)
startup:petclinic:profiling:Agent	16.78 s	17.26 s	[-6.9%; +1.3%] (no difference)
startup:petclinic:sca:Agent	17.52 s	16.73 s	[+0.4%; +9.1%] (maybe worse)
startup:petclinic:tracing:Agent	16.66 s	16.73 s	[-1.2%; +0.4%] (no difference)

Commit: a3536b2c · CI Pipeline · Benchmarking Platform UI

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Load and DaCapo benchmarks can be triggered manually in the GitLab pipeline. Results will appear in the Benchmarking Platform UI after completion.