Add flush for better debugging in run_tests.py

[aobolensk]

No description provided.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.17%. Comparing base (8d449d3) to head (a53bfc4).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #617   +/-   ##
=======================================
  Coverage   96.17%   96.17%           
=======================================
  Files          11       11           
  Lines         366      366           
  Branches      130      130           
=======================================
  Hits          352      352           
  Partials       14       14           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.