Add index for instrumentation helper classes

[sarahchen6]

What Does This Do

Add build-time index (helpers.index) for tracking instrumentation helper classes which maps modules to a helper class names table, and add a corresponding HelpersIndex for generating and reading these classes. Now CombiningTransformerBuilder looks up each module's helpers from this index instead of class-loading the module's $Muzzle at install. Fall back to helperClassNames() for runtime-configured modules.

Motivation

Without this index, helpers are resolved eagerly and negatively affect the startup time. Instead we can implement this index and replace the per-module class loads with one cheap read.

Additional Notes

This helper index uses InstrumenterIndex's module ordering, so we can use instrumentationId to index directly.

Contributor Checklist

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• Avoid using close, fix, or any linking keywords when referencing an issue
  Use solves instead, and assign the PR milestone to the issue
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Jira ticket: [PROJ-IDENT]

[dd-octo-sts]

🟡 Java Benchmark SLOs — Performance SLO warning (near threshold)

Suite	Status
Startup	🟡 warning

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	13.95 s	13.84 s	[-0.1%; +1.7%] (no difference)
startup:insecure-bank:tracing:Agent	12.89 s	12.93 s	[-0.9%; +0.2%] (no difference)
startup:petclinic:appsec:Agent	16.65 s	16.75 s	[-1.5%; +0.3%] (no difference)
startup:petclinic:iast:Agent	16.91 s	17.00 s	[-1.4%; +0.3%] (no difference)
startup:petclinic:profiling:Agent	16.84 s	16.85 s	[-1.0%; +0.9%] (no difference)
startup:petclinic:sca:Agent	16.67 s	16.58 s	[-0.3%; +1.4%] (no difference)
startup:petclinic:tracing:Agent	16.21 s	16.14 s	[-0.7%; +1.4%] (no difference)

Commit: f2354695 · 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.