Clean up buckets on e2e failure

[gargnitingoogle]

Description

It addresses two problems.

1. Deletion of buckets created by E2E run script. The code is there in place, but it doesn't fully work in the following ways
   • It deletes objects but not the bucket itself, at least not if the test run fails, as I have many times gone back and deleted buckets manually afterwards.
2. The deletion code doesn't get called if the script terminates early because of some test or environment issue causing a crash.

It also logs the bucket deletions if and when they are deleted.

Link to the issue in case of a bug fix.

b/409363794

Testing details

1. Manual - NA
2. Unit tests - NA
3. Integration tests - NA

Any backward incompatible change? If so, please explain.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.30%. Comparing base (1937ff7) to head (cb5ea5c).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3190      +/-   ##
==========================================
+ Coverage   78.28%   78.30%   +0.01%     
==========================================
  Files         125      125              
  Lines       17305    17305              
==========================================
+ Hits        13547    13550       +3     
+ Misses       3302     3300       -2     
+ Partials      456      455       -1     

Flag	Coverage Δ
unittests	78.30% <ø> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ 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.