8371788: Fix documentation for CollectedHeap::collect(GCCause)

Reviewed-by: ayang, iwalulya

src/hotspot/share/gc/g1/g1CollectedHeap.hpp

@@ -1040,9 +1040,6 @@ public:
   // old GC alloc region.
   bool is_old_gc_alloc_region(G1HeapRegion* hr);
 
-  // Perform a collection of the heap; intended for use in implementing
-  // "System.gc".  This probably implies as full a collection as the
-  // "CollectedHeap" supports.
   void collect(GCCause::Cause cause) override;
 
   // Try to perform a collection of the heap with the given cause to allocate allocation_word_size

src/hotspot/share/gc/parallel/parallelScavengeHeap.hpp

@@ -206,7 +206,6 @@ public:
 
   HeapWord* satisfy_failed_allocation(size_t size, bool is_tlab);
 
-  // Support for System.gc()
   void collect(GCCause::Cause cause) override;
 
   void collect_at_safepoint(bool full);

src/hotspot/share/gc/serial/serialHeap.hpp

@@ -139,9 +139,6 @@ public:
   // Callback from VM_SerialGCCollect.
   void collect_at_safepoint(bool full);
 
-  // Perform a full collection of the heap; intended for use in implementing
-  // "System.gc". This implies as full a collection as the CollectedHeap
-  // supports. Caller does not hold the Heap_lock on entry.
   void collect(GCCause::Cause cause) override;
 
   // Returns "TRUE" iff "p" points into the committed areas of the heap.

src/hotspot/share/gc/shared/collectedHeap.hpp

@@ -353,9 +353,7 @@ protected:
   // collection or expansion activity.
   virtual size_t unsafe_max_tlab_alloc() const = 0;
 
-  // Perform a collection of the heap; intended for use in implementing
-  // "System.gc".  This probably implies as full a collection as the
-  // "CollectedHeap" supports.
+  // Perform a collection of the heap of a type depending on the given cause.
   virtual void collect(GCCause::Cause cause) = 0;
 
   // Perform a full collection