RFR(T) : 8243929 : use @requires in serviceability/attach/AttachWithStalePidFile.java test

[Igor Ignatyev]

http://cr.openjdk.java.net/~iignatyev//8243929/webrev.00
> 7 lines changed: 1 ins; 6 del; 0 mod;

Hi all,

could you please review this trivial patch which updates AttachWithStalePidFile.java test to use @requires?
from JBS:
> serviceability/attach/AttachWithStalePidFile.java test can be run on windows and checks platform before executing any actual testing code. the modern faster and cleaner way to do it is using @requires.

JBS: https://bugs.openjdk.java.net/browse/JDK-8243929
webrev: http://cr.openjdk.java.net/~iignatyev//8243929/webrev.00

Thanks,
-- Igor