Intl: replace icutrim.py with ICU data slicer

[srl295]

In Node 0.12, I added icutrim.py and the config file icu_small.json to enable Node's "english only" default ICU packaging (aka icu-small).

ICU now has its own data slicer, see https://unicode-org.atlassian.net/browse/ICU-10923 (see the design doc at the top of that issue)

• Change Node to use this slicer where available with the goal of phasing out special code.
• Also, make sure that ICU's syntax is flexible enough to support node.

I'd encourage node people ( cc @nodejs/intl ) to visit the ICU issue and comment on the syntax.

Describe the solution you'd like
Less headache for Node maintainers! Less special purpose code!

Describe alternatives you've considered
do nothing - keep maintaining these python scripts

[mhdawson]

Sounds good to me.

[bnoordhuis]

And me. I second Jungshik's comment about the python script being the best option for us/them.

[targos]

@srl295 What's the status?

[srl295]

@targos nothing yet

[jasnell]

Ping @srl295 ... does this need to remain open?

[srl295]

@jasnell searched for this ticket because --with-intl=small-icu seems to be broken, could be a good time to bring the slicer in

[github-actions]

This issue/PR was marked as stalled, it will be automatically closed in 30 days. If it should remain open, please leave a comment explaining why it should remain open.

[srl295]

i'll at least mark it stalled. fyi @nodejs/i18n-api

[srl295]

So I'm setting myself a deadline here