Workers started via $.agent.start are not shut down in a synchronous manner, and it is possible the main thread terminates the process while a worker is writing its bytecode cache, which results in intermittent test failures.
Pull request: https://github.com/WebKit/WebKit/pull/776
Committed r294632 (250858@main): <https://commits.webkit.org/250858@main> Reviewed commits have been landed. Closing PR #776 and removing active labels.
<rdar://problem/93751431>