src: move trace_event.h include to internal header

Move the include from src/node.h to src/node_internals.h.

trace_event.h is not shipped in binary-only and headers-only tarballs,
making it currently impossible to build add-ons against them.

PR-URL: https://github.com/nodejs/node/pull/10959
Refs: https://github.com/nodejs/citgm/pull/226#issuecomment-274066280


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Matthew Loring <mattloring@google.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Stephen Belanger <admin@stephenbelanger.com>