Gradle config cache: agent-for-testing:jar

[trask]

Fixes ./gradlew :testing:agent-for-testing:jar --configuration-cache:

* What went wrong:
Configuration cache state could not be cached: field `mergePaths` of `org.gradle.api.java.archives.internal.DefaultManifestMergeSpec` bean found in field `manifestMergeSpecs` of `org.gradle.api.java.archives.internal.DefaultManifest` bean found in field `manifest` of task `:testing:agent-for-testing:jar` of type `org.gradle.api.tasks.bundling.Jar`: error writing value of type 'java.util.ArrayList'
> Cannot expand ZIP 'C:\src\opentelemetry-java-instrumentation-4\javaagent\build\libs\opentelemetry-javaagent-2.23.0-SNAPSHOT-base.jar' as it does not exist.