Add initial support for inlining.

* Add stack depth checking to function tester.
* Make context specialization clean up after itself.
* Add UpdateToAndIncrement to Inputs::iterator.
  Uses:iterator already provides this member function.
* Allow next node id in graph to be set.

R=mstarzinger@chromium.org, titzer@chromium.org

Review URL: https://codereview.chromium.org/453833003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23197 ce2b1a6d-e550-0410-aec6-3dcde31c8c00