Circular queues serve as a transport for communicating between
VM, stack sampler and analyzer threads. Logging requirements
for VM and stack sampler are completely different, that's why
I introduced two different versions of CQs.

Review URL: http://codereview.chromium.org/1047002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4159 ce2b1a6d-e550-0410-aec6-3dcde31c8c00