8026851: Remove unnecessary code in GenRemSet

Summary: Removed the GenRemSet::rem_set_name() since we only have one remset.
Reviewed-by: stefank, mgerdin, tschatzl

src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp

@@ -320,7 +320,7 @@ G1CollectorPolicy::G1CollectorPolicy() :
 
 void G1CollectorPolicy::initialize_flags() {
   _min_alignment = HeapRegion::GrainBytes;
-  size_t card_table_alignment = GenRemSet::max_alignment_constraint(rem_set_name());
+  size_t card_table_alignment = GenRemSet::max_alignment_constraint(GenRemSet::CardTable);
   size_t page_size = UseLargePages ? os::large_page_size() : os::vm_page_size();
   _max_alignment = MAX3(card_table_alignment, _min_alignment, page_size);
   if (SurvivorRatio < 1) {

src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp

@@ -665,8 +665,6 @@ public:
 
   BarrierSet::Name barrier_set_name() { return BarrierSet::G1SATBCTLogging; }
 
-  GenRemSet::Name  rem_set_name()     { return GenRemSet::CardTable; }
-
   bool need_to_start_conc_mark(const char* source, size_t alloc_word_size = 0);
 
   // Record the start and end of an evacuation pause.

src/share/vm/memory/collectorPolicy.cpp

@@ -105,7 +105,6 @@ bool CollectorPolicy::use_should_clear_all_soft_refs(bool v) {
 
 GenRemSet* CollectorPolicy::create_rem_set(MemRegion whole_heap,
                                            int max_covered_regions) {
-  assert(rem_set_name() == GenRemSet::CardTable, "unrecognized GenRemSet::Name");
   return new CardTableRS(whole_heap, max_covered_regions);
 }
 

src/share/vm/memory/collectorPolicy.hpp

@@ -151,7 +151,6 @@ class CollectorPolicy : public CHeapObj<mtGC> {
 
 
   virtual BarrierSet::Name barrier_set_name() = 0;
-  virtual GenRemSet::Name  rem_set_name() = 0;
 
   // Create the remembered set (to cover the given reserved region,
   // allowing breaking up into at most "max_covered_regions").
@@ -303,7 +302,6 @@ class TwoGenerationCollectorPolicy : public GenCollectorPolicy {
 
   int number_of_generations()                  { return 2; }
   BarrierSet::Name barrier_set_name()          { return BarrierSet::CardTableModRef; }
-  GenRemSet::Name rem_set_name()               { return GenRemSet::CardTable; }
 
   virtual CollectorPolicy::Name kind() {
     return CollectorPolicy::TwoGenerationCollectorPolicyKind;