Fix GraalVM nightly build failures

[whowes]

Nightly GraalVM builds are failing consistently in at least 3 places

• java-samples/native-image-sample (JUnit test discovery issue)
• java-datacatalog/google-cloud-datacatalog (com.google.cloud.datacatalog.v1beta1.it.ITSystemTest)
• java-datalabeling/google-cloud-datalabeling (com.google.cloud.datalabeling.it.ITSystemTest)

Tracking together until problems are clearly complex enough to justify separate issues