WeakSet::removeAllocator leaks WeakBlocks
https://bugs.webkit.org/show_bug.cgi?id=110228

Reviewed by Geoffrey Garen.

We need to return the WeakBlock to the BlockAllocator after the call to WeakBlock::destroy.

* heap/WeakSet.cpp:
(JSC::WeakSet::removeAllocator):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@143351 268f45cc-cd09-0410-ab3c-d52691b4dbfc