Introduce a microtask suppression scope and move microtask methods to isolate (Chromium issue 369503).

Re-enable Object.observe and add enforcement for security invariants.

Move cache line size calculation directly into CPU::FlushICache (Chromium issue 359977).

Generation of our home-grown memmove doesn't depend on serializer state anymore (Chromium issue 359977).

Fix |RunMicrotasks()| leaking reference to the last context being run on.

Object.defineProperty shouldn't be a hint that we're constructing a dictionary (Chromium issue 362870).

Performance and stability improvements on all platforms.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@21130 ce2b1a6d-e550-0410-aec6-3dcde31c8c00