Invert parameters of all call to AssertEquals in Spinner tests

[fedejeanne]

They were being used wrong. Also, add the index of the array in one of the tests for better debugging.

[github-actions]

Test Results

   506 files  + 1     506 suites  +1   8m 51s ⏱️ -1s
 4 341 tests +37   4 327 ✅ +35   14 💤 +3  0 ❌  - 1 
16 597 runs  +37  16 488 ✅ +35  109 💤 +3  0 ❌  - 1 

Results for commit 9a666ab. ± Comparison against base commit 18ac3b4.

[fedejeanne]

Failing API checks are unrelated since I didn't modify those classes