RFR: 8192807: testlibrary_tests/TestMutuallyExclusivePlatformPredicates.java fail due to new method in Platform.java

[Stefan Johansson]

Hi,

Please review this small fix for tier1 failure reported in:
https://bugs.openjdk.java.net/browse/JDK-8192807

Webrev:
http://cr.openjdk.java.net/~sjohanss/8192807/00/

Summary:
The newly added method in Platform.java was not added to a MethodGroup 
in the test. This change adds the method to the IGNORED group and also 
adds output to the assertion to simplify debugging in the future.

Testing:
* The affected test both locally and through M5 (running now).

Thanks,
Stefan