Some Heap cleanup.

Some Heap cleanup.

Reviewed by Beth Dakin.

* heap/MarkedBlock.cpp:
(JSC::MarkedBlock::blessNewBlock): Removed blessNewBlockForSlowPath()
because it was unused; renamed blessNewBlockForFastPath() to blessNewBlock()
since there is only one now.

* heap/MarkedBlock.h: Removed ownerSet-related stuff since it was unused.
Updated mark bit overhead calculation. Deployed atomsPerBlock in one
place where we were recalculating it.

* heap/MarkedSpace.cpp:
(JSC::MarkedSpace::addBlock): Updated for rename.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@95596 268f45cc-cd09-0410-ab3c-d52691b4dbfc