Rollup changes for Helgrind:

Rollup changes for Helgrind:

* Add new client request VALGRIND_HG_CLEAN_MEMORY_HEAPBLOCK.  This is
  like VALGRIND_HG_CLEAN_MEMORY but doesn't take an address range.
  Instead it takes a single argument which is supposed to be a pointer
  to the start of, or anywhere within, a heap allocated block.
  Helgrind then finds the block and paints it as belonging to the
  calling thread.  This is needed for correctly describing the
  behaviour of threadsafe reference counting when applied to classes
  involving inheritance of release methods or involving multiple
  inheritance.

* Add statistics counters for all basic VTS operations (tick, join,
  cmpLEQ, cmp_structural).

* Rewrite VTS__cmp_structural to be much faster.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@11123