src: WIP use external array data to store pointer

Instead of assigning the class as an internal field, assign the memory
pointer as external array data.

NOTES:
- changes to node_internals.h and tls_wrap.cc are causing
  test-tls-ticket-cluster to die since args.This() has no external array
  data. Still investigating.
src: WIP macroify wrapping instances

Want to make it easy to revert.
object_wrap: WIP switch to external array data

THIS IS A POTENTIALLY MASSIVE BREAKAGE. It was done for consistency and
it fixes the tls test failure from before.

Definitely needs review/feedback from the team.
src: WIP remove incrementing field count

Now that the internal field count is not used, no need to increment it.

Also removed some now unused directives.