Fixup slow cli exit time

[guybedford]

This fixes up the CLI exit time by almost a second !

[codecov-io]

Codecov Report

Merging #268 into master will decrease coverage by 0.08%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master     #268      +/-   ##
==========================================
- Coverage   74.23%   74.15%   -0.09%     
==========================================
  Files          17       17              
  Lines         885      886       +1     
==========================================
  Hits          657      657              
- Misses        228      229       +1

Impacted Files	Coverage Δ
src/cli.js	59.23% <0%> (-0.38%)	⬇️

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