Version 3.27.2 (based on bleeding_edge revision r21275)

Harden %SetIsObserved with RUNTIME_ASSERTs (Chromium issue 371782).

Drop unused static microtask API.

Introduce an api to query the microtask autorun state of an isolate.

Performance and stability improvements on all platforms.

git-svn-id: https://v8.googlecode.com/svn/trunk@21276 ce2b1a6d-e550-0410-aec6-3dcde31c8c00