8231174: (fs) FileTime should have 100ns resolution (win)

[Alan Bateman]

On 20/09/2019 19:40, Brian Burkhalter wrote:
> https://bugs.openjdk.java.net/browse/JDK-8231174
> http://cr.openjdk.java.net/~bpb/8231174/webrev.00/
>
> Change the file timestamp resolution on Windows from microseconds to intervals of 100 nanoseconds. Only systems where the working directory is NTFS are currently verified by the test.
>
This changes the implementation to use BigInteger in the conversion from 
long <--> FileTime which seems a bit overkill. I think we should explore 
other alternatives before going that route.

-Alan