Fix some out-of-line constant pool garbage collection bugs.

This CL fixes some bugs in the out of line constant pool implementation when
constant pools are GCed.  Namely:
  - Push/Pop pp register in exit frames and VisitPointer on it to ensure it is
    updated if the ConstantPoolArray is moved by GC.
  - Mark pp as a SafePoint Register for optimized functions.
  - Ensure that StandardFrame::IterateExpressions also iterates over the
    constant pool pointer in the stackframe.
  - Fix calculation of last_ptr_offset in ConstantPoolArray body iterator.
  - Make ensure that CONSTANT_POOL_ARRAY_TYPE is a pointer object InstanceType.

R=ulan@chromium.org

Review URL: https://codereview.chromium.org/123263005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18473 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Remove flag track-allocation-sites.

The flag has been on in the build for ~9 months, and we aren't likely to turn it off. The only customer of the flag is a set of tests that want to verify transitioning behavior in isolation. This CL removes the flag and updates those tests to get what they want without the flag.

R=verwaest@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=18385

Review URL: https://codereview.chromium.org/104923010

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18474 ce2b1a6d-e550-0410-aec6-3dcde31c8c00