chore(test): add dtslint files and script

[cartant]

Description:

This PR adds dtslint to the full-validation build. The dtslint-related files are in the spec-dtslint directory.

The type tests for the zip factory function and the zip operator have been included so that they are tested using dtslint's expectations. The original type tests have not been removed.

Related issue (if exists): #3823

[rxjs-bot]

	Warnings
⚠️	❗ Big PR (1)

(1) : Pull Request size seems relatively large. If Pull Request contains multiple changes, split each into separate PR will helps faster, easier review.

Generated by 🚫 dangerJS

[coveralls]

Coverage remained the same at 96.962% when pulling 6c4008c on cartant:issue-3823 into a3323fc on ReactiveX:master.

[cartant]

Hmm. I hadn't noticed that npm had made such a mess of the lock file. I will try to fix it up a little.

[kwonoj]

though lockfile itself seems ok-change?

[cartant]

I'm just going to re-apply the commits and do a single install of dtslint using the current lock file from master. I'm not going to manually mess with the lock file.

The initial commits and install of dtslint were from some time ago and I had to re-install dtslint to get an updated dependency - as I'm creating this PR on a different computer - and I really don't think that the lock file should have as many changes in it as it appears to have. I'd like to be sure that what was in the node_modules directory on this computer hasn't messed with the lock file. npm infuriates me sometimes.

[cartant]

@kwonoj I'm done messing with this. I don't know why npm does some of the things that it does. E.g. it appears to have changed resolved from false to an empty string for a bunch of entries.

Anyway, I'm at least confident that there wasn't any filth in node_modules that could have effected an unwarranted changes to the lock file.