8231254: (fs) Add test for macOS Catalina changes to protect system software

Fri Sep 20 00:01:27 UTC 2019

> On Sep 19, 2019, at 8:32 AM, Brian Burkhalter <brian.burkhalter at oracle.com> wrote:
> 
> https://bugs.openjdk.java.net/browse/JDK-8231254
> http://cr.openjdk.java.net/~bpb/8231254/webrev.00/
> 
> This test verifies that “/“ is read-only and any existing directories in /usr/share/firmlinks are not.
> 
> Probably testing other APIs on well known files in the read-only volume should be added as well.

I added some other tests to check a smattering of NIO API calls applied to locations in both the system (read-only) and data (read-write) volumes. These are in the checkSystemVolume() and checkDataVolume() methods.

http://cr.openjdk.java.net/~bpb/8231254/webrev.01/

Thanks,

Brian