Add RuntimeState and keylogger to it

[mstoykov]

Based on #2485 (comment)
fixes #1043
Changelog entry (under new features):

Add the ability to dump SSL keys while making TLS connections, which than can be used to decrypt the whole traffic k6 generates. 

This is done through setting the `SSLKEYLOGFILE` to some file path that and running k6. This will populate the file with the keys, and then you can use Wireshark to capture the traffic , decrypt it and use that for debugging. 

You can look at how this is done with curl [here](https://daniel.haxx.se/blog/2018/01/15/inspect-curls-tls-traffic/).

[na--]

👍 Something like this LGTM. I think you're not covering the case testTypeArchive branch in initializeFirstRunner(), so some further refactoring might be needed, but I like the general approach

[mstoykov]

I think you're not covering the case testTypeArchive branch in initializeFirstRunner(), so some further refactoring might be needed, but I like the general approach

Yeah, I also will remove the functions which don't take teh state, but didn't want to do any more changes than needed to actually get a PoC

[mstoykov]

afero is striking again with it's strange bugs 🤦 I literally couldn't make OpenFile create a file with fs.OsFs with no version I tried and I htink that MemMapFs got fixed in one the very last releases :(. This actually tunred out to be me using a wrapped fs 🤦

Moving tlsconfig out of js.Runner seemed like way too big of a yak shave to start on it - given the amount of refactoring I already needed to do to make this possible at all -so for now i just skip tls checking.

[na--]

LGTM besides #2487 (review)

[mstoykov]

I also made this small unrelated change b710000 ... kind of wonder if I should make the require an assert as currently when something fails - there are no logs .. Or maybe by default it can also dump at least the stderr 🤷

[na--]

LGTM! 🎉 ❤️

[oleiade]

Tested and approved on Windows! Great job, and super useful indeed! 🪟 🎉

[kkriegkxs]

Good stuff! Thanks @mstoykov
Also glad you went with the standard env var ;)