Remove win32 properly (Previous update had faulty logic)
Add Alpine/aarch64 for JDK21
Add a comment explaining that JDK8 for Linux/s390x is not shipped.
Note that at present I am leaving the three "absent" platforms for JDK21 in the checks as we do not have any intention to avoid shipping them in the future if feasible.
Updates for JDK21 releases:
Note that at present I am leaving the three "absent" platforms for JDK21 in the checks as we do not have any intention to avoid shipping them in the future if feasible.