testutil/compose: run smoke tests in parallel

[corverroos]

Runs smoke tests in parallel for faster feedback.

category: test
ticket: #631

[corverroos]

Decreases smoke test duration from 5m to 2.5m.

[codecov]

Codecov Report

Merging #722 (6378850) into main (87b91c1) will decrease coverage by 0.47%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #722      +/-   ##
==========================================
- Coverage   54.02%   53.54%   -0.48%     
==========================================
  Files         104      104              
  Lines       10146    10146              
==========================================
- Hits         5481     5433      -48     
- Misses       3860     3908      +48     
  Partials      805      805              

Impacted Files	Coverage Δ
core/qbft/qbft.go	71.67% <0.00%> (-9.88%)	⬇️
core/leadercast/transport.go	75.14% <0.00%> (-1.19%)	⬇️

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