RFR(T) : 8209917 : fix TODO in GatherDiagnosticInfoObserver

[Igor Ignatyev]

http://cr.openjdk.java.net/~iignatyev//8209917/webrev.00/index.html
> 11 lines changed: 0 ins; 3 del; 8 mod; 

Hi all,

could you please review this small and trivial clean up in failure_handler library?

webrev: http://cr.openjdk.java.net/~iignatyev//8209917/webrev.00/index.html
JBS: https://bugs.openjdk.java.net/browse/JDK-8209917
testing: make test TEST=failure-handler; tier1

Thanks,
-- Igor