Implemented Load IC support for loading properties from primitive values to avoid perpetual soft deopts.  (Chromium issue 242512)

Implemented Freeing of PerThreadAssertData when possible to avoid memory leak. (Chromium issue 246567)

Removed V8_USE_OLD_STYLE_PERSISTENT_HANDLE_VISITORS.

Performance and stability improvements on all platforms.

git-svn-id: http://v8.googlecode.com/svn/trunk@14954 ce2b1a6d-e550-0410-aec6-3dcde31c8c00