deps: update v8 to 3.24.40
src: update to v8 3.24 APIs
deps: backport a6fed7c5 from v8's trunk
deps: allow allocations in gc epilogue/prologue

See https://codereview.chromium.org/177243012/
node: fix exported signatures of MakeCallback

fix #7302
src, test: fix up ObjectWrap, `make test-addons`

V8 was upgraded from 3.22 to 3.24 in commit 1c7bf24.  Upgrade source
files in test/addons/ and automatically generated tests from
doc/api/addons.markdown to the new V8 API.

This coincidentally fixes a bug in src/node_object_wrap.h where it was
still using the old V8 weak persistent handle interface, which is gone
in 3.24.
WIP: upgrade libuv to latest and greatest
src: fix use of uv_cwd, len includes the NULL byte
src: update uv callbacks after API changes

async, timer, prepare, idle and check handles no longer get a status
parameter since they can never fail.