sdk/log: add TestRecordMethodsInputConcurrentSafe

[pellared]

Why

Towards #7364

I want to split it into a few PRs as otherwise it would be a big PR which would be hard to review.

I plan to add benchmarks after this one.

What

Add a unit test reproducing all cases from #7364 (comment) when

if race() {
	t.Skip("TODO: Fix bug https://github.com/open-telemetry/opentelemetry-go/issues/7364.")
}

is removed.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.5%. Comparing base (6180f83) to head (d44cd3b).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #7378   +/-   ##
=====================================
  Coverage   85.5%   85.5%           
=====================================
  Files        274     274           
  Lines      24614   24614           
=====================================
  Hits       21049   21049           
  Misses      3186    3186           
  Partials     379     379           

🚀 New features to boost your workflow:

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