JDK-8343190 was in mainline for a few days. I have now caught the case where JTReg fails to build due to network failure (wget exit code 4). It does not look that retries added by JDK-8343190 work: we end up retrying for 25 minutes and then failing anyway.

So I would suspect that is a worker configuration issue rather than transient network issue. It does not make sense to wait for 25 minutes without a high chance of success. This means we are better off without JDK-8343190, and can back it out.

There is an alternative to all this we can explore separately: build external dependencies on schedule for `master` branch, so that they can be used by branches without breakages in individual PRs. (JDK-8343546).