deps: re-implement debugger-agent
cluster: do not signal children in debug mode

Do not send signal to children if they are already in debug mode.
Node.js on Windows does not register signal handler, and thus calling
`process._debugProcess()` will throw an error.
src, test: fixup after v8 update

Because of behavior change of some V8 APIs (they mostly became more
    strict), following modules needed to be fixed:

* crypto: duplicate prototype methods are not allowed anymore
* contextify: some TryCatch trickery, the binding was using it
incorrectly
* util: maximum call stack error is now crashing in a different place
test: fix debug-signal-cluster after da update

The cluster children are hitting breakpoint at `cluster.onread` and
hanging on a Semaphore wait now. This prevents them from disconnecting
gracefully. Considering that the test is checking different thing, the
cluster children needs to be force killed from the grand parent process.