Rename double-remove TraceState tests and exercise a non-first entry

[thswlsqls]

Description

• Follows up on two review comments left on Fix TraceStateBuilder.remove corrupting the builder when the same key is removed twice #8613, which were submitted after that PR had already been merged.
• Renames removeTwice, removeTwice_KeepsRemainingEntry and removeTwice_KeepsRemainingEntries to removeSameKeyTwice*. All three remove the same key, which the previous names did not say.
• removeSameKeyTwice_KeepsRemainingEntries now removes SECOND_KEY rather than FIRST_KEY. ArrayBasedTraceStateBuilder.remove scans entries from the front, so removing the first key always matches on the first iteration; removing a middle key covers a later slot for the first time.
• Test-only: no production code, public API or asserted behavior changes.
• Comments being addressed: Fix TraceStateBuilder.remove corrupting the builder when the same key is removed twice #8613 (comment) and Fix TraceStateBuilder.remove corrupting the builder when the same key is removed twice #8613 (comment)

Testing done

• ./gradlew :api:all:test --tests "io.opentelemetry.api.trace.TraceStateTest" — 41 tests passed, 0 skipped. The three renamed methods show up in the test report, so the rename did not drop them.
• ./gradlew :api:all:check — passed (test, spotless, ErrorProne/NullAway, jApiCmp).
• jApiCmp produced no docs/apidiffs/current_vs_latest/ update.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: thswlsqls / name: Eunbin Son (a75c7ab)

[opentelemetry-pr-dashboard]

Pull request dashboard status

Waiting on the author · refreshed 2026-07-31 13:26 UTC

Move out of draft to request review.

Status above doesn't look right?

• Just replied or pushed? Anything around or after the refresh time above may not be picked up yet — give it a few minutes.
• Anything look wrong? Report it with what you expected; it helps us improve the dashboard.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.45%. Comparing base (a0f8f92) to head (a75c7ab).

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #8672   +/-   ##
=========================================
  Coverage     91.45%   91.45%           
  Complexity    10462    10462           
=========================================
  Files          1021     1021           
  Lines         27680    27680           
  Branches       3244     3244           
=========================================
  Hits          25316    25316           
  Misses         1620     1620           
  Partials        744      744           

☔ View full report in Codecov by Harness.
📢 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.