neotest: coverage collection polishing

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 7.14286% with 26 lines in your changes missing coverage. Please review.

Project coverage is 85.19%. Comparing base (a924253) to head (c1444d4). Report is 6 commits behind head on master.

Files with missing lines	Patch %	Lines
pkg/neotest/coverage.go	4.00%	23 Missing and 1 partial :warning:
pkg/neotest/basic.go	33.33%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #3616 +/- ## ======================================= Coverage 85.19% 85.19% ======================================= Files 333 333 Lines 39009 39022 +13 ======================================= + Hits 33232 33245 +13 - Misses 4207 4210 +3 + Partials 1570 1567 -3 ```

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[AnnaShaleva]

It'd be nice to know the reason for sorting from the commit message.

I'm writing an issue about that.

[AnnaShaleva]

OK, no issue required for sorting.