JS: Extra taint-steps to support CVE

[erik-krogh]

This PR almost gets a TP/TN for CVE-2020-15152 (one callgraph related step missing).

Does the following:

• Add support for direct callbacks to require("net").createServer((socket) => {...}).
  Previously only require("net").createServer().on("connection", (socket) => {...}) was supported.
  (Also adds tls as another module that has the same createServer method).

• Adds (new require("net").Socket()).connect(..) as a ClientRequest.
  Neither getAResponseDataNode nor getADataNode are needed for the CVE, but I added them for completeness.

• Drive-by refactorization of arrayFunctionTaintStep.

• Taint step for require("bluebird").mapSeries().
  (mapSeries is unique to bluebird).
  Only the argument -> parameter step is needed for the CVE, but I added the return -> call step for completeness.

• Adds lots of taint-steps for underscore methods.
  I took a quick walk through here: https://underscorejs.org/#each, and added taint-steps for the methods that had obvious taint-steps.
  Only _.compact(array) is needed for the CVE.

An evaluation on nightly looks fine fine.
(UnsafeJQueryPlugin.ql failed for azure-sdk-for-node on both branches - that was after my recent PR - I'm investigating).

[asgerf]

What do you mean by "non-function"?

[erik-krogh]

I mean that I don't include any of the Underscore methods that involve functions. (E.g. _.bind(), _.partial(), _.throttle()).
They are called Function Functions in the Underscore documentation.

Should I update the docstring to something else?