Make sure ExternalCallbackScope is always created when VM state changes to EXTERNAL

ExternalCallbackScope is used to let CPU profiler know which API callback is being executed. Whenever such callback is called we should create VMState<ETERNAL> and ExternalCallbackScope. This patch fixes several places where VMState<ETERNAL> went without ExternalCallbackScope.

BUG=244580
R=dcarney@chromium.org, svenpanne@chromium.org

Review URL: https://codereview.chromium.org/17059005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15249 ce2b1a6d-e550-0410-aec6-3dcde31c8c00