fix race condition in deadline integration test

[marten-seemann]

No description provided.

[codecov]

Codecov Report

Merging #3165 (e8b09bc) into master (5f2cf04) will increase coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3165      +/-   ##
==========================================
+ Coverage   85.38%   85.39%   +0.01%     
==========================================
  Files         132      132              
  Lines        9831     9831              
==========================================
+ Hits         8394     8395       +1     
+ Misses       1063     1062       -1     
  Partials      374      374              

Impacted Files	Coverage Δ
internal/utils/rand.go	75.00% <0.00%> (+12.50%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 5f2cf04...e8b09bc. Read the comment docs.