Introduce API to temporarily interrupt long running JavaScript code.

It is different from termination API as interrupted JavaScript will continue to execute normally when registered InterruptCallback returns.

  /**
   * Request V8 to interrupt long running JavaScript code and invoke
   * the given |callback| passing the given |data| to it. After |callback|
   * returns control will be returned to the JavaScript code.
   * At any given moment V8 can remember only a single callback for the very
   * last interrupt request.
   * Can be called from another thread without acquiring a |Locker|.
   * Registered |callback| must not reenter interrupted Isolate.
   */
  void RequestInterrupt(InterruptCallback callback, void* data);

  /**
   * Clear interrupt request created by |RequestInterrupt|.
   * Can be called from another thread without acquiring a |Locker|.
   */
  void ClearInterrupt();

Fix Hydrogen SCE pass to avoid eliminating stack guards too aggressively. Only normal JavaScript functions are guaranteed to have stack guard in the prologue. If function is a builtin or has a custom call IC it will lack one.

BUG=
R=danno@chromium.org, dcarney@chromium.org

Review URL: https://codereview.chromium.org/102063004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18363 ce2b1a6d-e550-0410-aec6-3dcde31c8c00