Trace scavenger throughput.

BUG=
R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/487753003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23195 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Expose well-known Symbols to C++ API.

BUG=341423
LOG=Y
R=arv@chromium.org, dcarney@chromium.org, rossberg@chromium.org

Review URL: https://codereview.chromium.org/483173002

Patch from Yutaka Hirano <yhirano@chromium.org>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23196 ce2b1a6d-e550-0410-aec6-3dcde31c8c00