lookup: avoid browser testing for through2

[richardlau]

Use a different npm script to avoid browser tests for through2 and sort
the keys for the through2 entry in lookup.json.

Fixes: #809

Checklist

• npm test passes
• contribution guidelines followed
  here

[codecov-commenter]

Codecov Report

Merging #810 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #810   +/-   ##
=======================================
  Coverage   96.17%   96.17%           
=======================================
  Files          30       30           
  Lines         889      889           
=======================================
  Hits          855      855           
  Misses         34       34           

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[richardlau]

CI: https://ci.nodejs.org/view/Node.js-citgm/job/citgm-smoker-pipeline/118/flowGraphTable/

(Looks like failures on AIX and Windows)

[richardlau]

Added skips for AIX and Windows.

New CI: https://ci.nodejs.org/view/Node.js-citgm/job/citgm-smoker-pipeline/119/flowGraphTable/
(citgm doesn't honour skip/flaky).
Retrying with citgm-all: https://ci.nodejs.org/view/Node.js-citgm/job/citgm-smoker-pipeline/120/flowGraphTable/ (✔️)