Testing: Add missing t.Parallel to speed up tests

[martijnvans]

Description

Corey noticed tests were slow, and after some digging I found:

--- PASS: TestPartialSuccess (3231.11s)
    --- PASS: TestPartialSuccess/windows-2016-core (441.91s)
    --- PASS: TestPartialSuccess/sql-std-2019-win-2019 (488.53s)
    --- PASS: TestPartialSuccess/windows-2022 (494.28s)
    --- PASS: TestPartialSuccess/windows-2016 (532.98s)
    --- PASS: TestPartialSuccess/windows-2019 (455.43s)
    --- PASS: TestPartialSuccess/windows-2019-core (412.52s)
    --- PASS: TestPartialSuccess/windows-2022-core (405.47s)

This normally looks different (a tiny number after the test name, TestPartialSuccess in this case) and indicates that the tests were running in series, not in parallel. Easy fix.

Related issue

None

How has this been tested?

automated tests should be enough.

Checklist:

• Unit tests
  • Unit tests do not apply.
  • Unit tests have been added/modified and passed for this PR.
• Integration tests
  • Integration tests do not apply.
  • Integration tests have been added/modified and passed for this PR.
• Documentation
  • This PR introduces no user visible changes.
  • This PR introduces user visible changes and the corresponding documentation change has been made.
• Minor version bump
  • This PR introduces no new features.
  • This PR introduces new features, and there is a separate PR to bump the minor version since the last release already.
  • This PR bumps the version.

[franciscovalentecastro]

LGTM! I missed this from my fluent-bit upgrade PR (#1559). Thanks for adding it 🙏 !