8315149: Add hsperf counters for CPU time of internal GC threads

src/hotspot/share/runtime/cpuTimeCounters.hpp

@@ -49,7 +49,7 @@ class CPUTimeGroups : public AllStatic {
   static bool is_gc_counter(CPUTimeType val);
 };
 
-class CPUTimeCounters: public CHeapObj<mtGC> {
+class CPUTimeCounters: public CHeapObj<mtServiceability> {
 private:
   // CPUTimeCounters is a singleton instance.
   CPUTimeCounters();
@@ -74,7 +74,7 @@ class CPUTimeCounters: public CHeapObj<mtGC> {
   }
 
   static void initialize() {
-    assert(get_instance() == nullptr, "we can only allocate one CPUTimeCounters object");
+    assert(_instance == nullptr, "we can only allocate one CPUTimeCounters object");
     _instance = new CPUTimeCounters();
   }