std::sort is a template, so it can be inlined more aggressively. Also, it's
O(n log n), while libc's qsort is O(n^2)

BUG=2639

Review URL: https://codereview.chromium.org/14315005

Patch from Jochen Eisinger <jochen@chromium.org>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14406 ce2b1a6d-e550-0410-aec6-3dcde31c8c00