Add a toggle that turns automatic high-degree node extraction off

[martinwicke]

This adds a toggle (next to "trace inputs") which turns automatic high-degree node extraction off.

• Motivation for features / changes
  Automatic aux node creation can break the graph up in unwanted ways. For some graphs, the high-degree heuristic is not useful (graphs that have high-degree internal nodes, e.g., if you concatenate lots of towers or some such)

• Technical description of changes
  This adds an argument to the hierarchy constructor which if passed, avoids calling the high-degree node extraction code. It also removes the hard-coded PARAM entry for node extraction (which turned off all node extraction, but wasn't user settable).

• Detailed steps to verify changes work correctly (as executed by you)

  • build
  • upload graph known to be broken apart verify it's broken apart
  • toggle "auto-extract high-degree nodes"
  • verify graph changes, and high-degree nodes are not extracted

• Alternate designs / implementations considered

  • Make the in/out degree triggering extraction configurable (probably not worth it)
  • Turn off high-degree extraction altogether instead of providing the option (would work for me, but I'm hesitant to break others in this manner)
  • Rely more heavily on op list extraction (this might work, but I lack the expertise to come up with a good op list)

[psybuzz]

Thanks for contributing this PR!

[martinwicke]

There's some lint left, I'll fix this when it's otherwise ready.

Can you take a look whether this is better?

[psybuzz]

LGTM % minor comments, I'm pleased to see this happen!

If the Prettier linting ends up being too painful, let me know and I can push a commit from my end as well.

[martinwicke]

Happy to run prettier. It does propose some changes that are unrelated to my edits though -- do you want those?

[martinwicke]

I didn't add the unrelated lint things for now.

[psybuzz]

It does propose some changes that are unrelated to my edits though -- do you want those?

I'm not sure why there would be unrelated edits, unless maybe Prettier is run from another directory (running from "tensorboard_repo_dir/tensorboard/" might not pickup our settings).

That said, I checked out your latest patch, ran Prettier locally, and it passed the linter locally, so it seems good to me

[martinwicke]

Cool. Merge at will then. I can, for historical reasons, but I don't think I should.