Move simplecov patch to an overlay in our tree instead of using a forked simplecov repo

[p-datadog]

What does this PR do?

Moves the patch for simplecov not being able to combine jruby and MRI coverage reports to our repo.

Motivation:

bundler is constantly asking to reinstall simplecov from the fork

Change log entry
None

Additional Notes:

How to test the change?

[github-actions]

Thank you for updating Change log entry section 👏

^{Visited at: 2025-01-08 05:00:05 UTC}

[datadog-datadog-prod-us1]

Datadog Report

Branch report: simplecov-overlay-patch
Commit report: ee1a753
Test service: dd-trace-rb

✅ 0 Failed, 22497 Passed, 1488 Skipped, 6m 1.72s Total Time
❄️ 1 New Flaky

New Flaky Tests (1)

• Server internal tracer traces the looping scheduled wait - rspec - Last Failure

  Expand for error

   Wait time exhausted!
   
   Failure/Error: raise('Wait time exhausted!')
   
   RuntimeError:
     Wait time exhausted!
   ./spec/support/synchronization_helpers.rb:97:in \`try_wait_until'
   ./spec/support/synchronization_helpers.rb:26:in \`expect_in_fork'
   ./spec/datadog/tracing/contrib/sidekiq/support/helper.rb:52:in \`expect_in_sidekiq_server'
   ./spec/datadog/tracing/contrib/sidekiq/server_internal_tracer/scheduled_poller_spec.rb:49:in \`block (2 levels) in <top (required)>'
   ...
  

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-01-08 05:23:45

Comparing candidate commit ee1a753 in PR branch simplecov-overlay-patch with baseline commit d5f88ea in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 31 metrics, 2 unstable metrics.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.75%. Comparing base (9605f99) to head (ee1a753).
Report is 3 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #4263   +/-   ##
=======================================
  Coverage   97.74%   97.75%           
=======================================
  Files        1353     1353           
  Lines       82392    82392           
  Branches     4224     4224           
=======================================
+ Hits        80536    80540    +4     
+ Misses       1856     1852    -4     

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[ivoanjo]

👍 LGTM. This workaround seems much nicer than needing to carry our own fork just for simplecov-ruby/simplecov#972 .

[TonyCTHsu]

Awesome!