Add %_DebugBreakInOptimizedCode() pseudo function call to insert int3/stop instructions into optimized code

R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/17870002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15392 ce2b1a6d-e550-0410-aec6-3dcde31c8c00