src: Node Tracing Controller

This commit adds support for trace-event tracing to Node.js. It provides
a mechanism to centralize tracing information generated by V8, Node
core, and userspace code. It includes:

 - A trace writer responsible for serializing traces and cycling the
   output files so that no individual file becomes to large.
 - A buffer for aggregating traces to allow for batched flushes.
 - An agent which initializes the tracing controller and ensures that
   trace serialization is done on a separate thread.
 - A set of macros for generating trace events.
 - Tests and documentation.

Author: Raymond Kang <raymondksi@gmail.com>
Author: Kelvin Jin <kelvinjin@google.com>
Author: Matthew Loring <mattloring@google.com>
Author: Jason Ginchereau <jasongin@microsoft.com>

PR-URL: https://github.com/nodejs/node/pull/9304



Reviewed-By: Trevor Norris <trev.norris@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Josh Gavant <josh.gavant@outlook.com>