util: Add debuglog, deprecate console lookalikes
test: Fix test-deprecation-flags

Test typos missed in util deprecation commit
v8: upgrade to v3.19.3
v8: reapply floating patches
src: upgrade to new v8 api

Small change that Context::New requires an isolate and returns Local
instead of Persistent.
src: remove unused comment

Now that Context::New(Isolate*) returns Local, the removed comment is
no longer applicable that there is a Persistent which will need to be
disposed.