6624765: Guarantee failure "Unexpected dirty card found"

In verification take into account partial coverage of a region by a card and expansion of the card table.

Reviewed-by: ysr, apetrusenko

hotspot/src/share/vm/memory/genRemSet.hpp

@@ -91,8 +91,15 @@ public:
   virtual void verify() = 0;
 
   // Verify that the remembered set has no entries for
-  // the heap interval denoted by mr.
-  virtual void verify_empty(MemRegion mr) = 0;
+  // the heap interval denoted by mr.  If there are any
+  // alignment constraints on the remembered set, only the
+  // part of the region that is aligned is checked.
+  //
+  //   alignment boundaries
+  //   +--------+-------+--------+-------+
+  //         [ region mr              )
+  //            [ part checked   )
+  virtual void verify_aligned_region_empty(MemRegion mr) = 0;
 
   // If appropriate, print some information about the remset on "tty".
   virtual void print() {}