RFR (S): 8235247: WorkerDataArray leaks C heap memory for associated work items

[Thomas Schatzl]

Hi all,

   can I have reviews for this fix to a small memory leak, leaking a few 
100 bytes per GC?

WorkerDataArray does not delete linked thread work items, so code that 
temporarily creates and uses them leaks.

Currently this is only a variant of WeakProcessor::weak_oops_do() that 
seems to be only used by G1.

Thanks go to M. Vidstedt for finding and reporting the issue.

CR:
https://bugs.openjdk.java.net/browse/JDK-8235247
Webrev:
http://cr.openjdk.java.net/~tschatzl/8235247/webrev/
Testing:
manual testing using NMT; i did not observe other leaks given the 
example program attached to the CR.

Thanks,
   Thomas