8050973: CMS/G1 GC: add missing Resource and Handle mark

Summary: Add Resource/HandleMark in the work() method of some AbstractGangTask to reclaim these resources earlier.
Reviewed-by: tschatzl, goetz

src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp

@@ -6051,6 +6051,8 @@ public:
 };
 
 void CMSRefProcTaskProxy::work(uint worker_id) {
+  ResourceMark rm;
+  HandleMark hm;
   assert(_collector->_span.equals(_span), "Inconsistency in _span");
   CMSParKeepAliveClosure par_keep_alive(_collector, _span,
                                         _mark_bit_map,

src/share/vm/gc_implementation/g1/concurrentMark.cpp

@@ -2403,6 +2403,8 @@ public:
   }
 
   virtual void work(uint worker_id) {
+    ResourceMark rm;
+    HandleMark hm;
     CMTask* task = _cm->task(worker_id);
     G1CMIsAliveClosure g1_is_alive(_g1h);
     G1CMKeepAliveAndDrainClosure g1_par_keep_alive(_cm, task, false /* is_serial */);