Windows CI caught real over-reach. When another holder has write.lock, Windows
raises the sharing violation before Lucene can turn it into a
LockObtainFailedException, so it arrives as a plain IOException. Repairing anything
that is not a recognised lock conflict then meant deleting the index the other
holder was using -- exactly the second-instance case the retry exists for.
An IOException naming Lucene's write lock now counts as a lock conflict. Matching
the file name rather than the message wording keeps it working on non-English
Windows. The end-to-end test asserts the property instead of the exception type,
since the type legitimately differs by platform.
Co-authored-by: rmcrackan <rmcrackan@gmail.com>