[Tests] Remove not needed usings in the CoreData and CoreFoundation tests

[mandel-macaque]

No description provided.

[vs-mobiletools-engineering-service2]

❌ [PR Build] Tests failed on Build ❌

Tests failed on Build.

• Azure DevOps
• Html Report (VSDrops)

API diff

✅ API Diff from stable

View API diff

• iOS vsdrops gist
• macOS vsdrops gist
• tvOS vsdrops gist
• watchOS vsdrops gist
• macCatiOS vsdrops gist
• macCat vsdrops gist

View dotnet API diff

• dotnet-iOS vsdrops gist
• dotnet-macOS vsdrops gist
• dotnet-tvOS vsdrops gist
• dotnet-MacCatalyst vsdrops gist

View dotnet legacy API diff

• dotnet-legacy-iOS vsdrops gist
• dotnet-legacy-macOS vsdrops gist
• dotnet-legacy-tvOS vsdrops gist
• dotnet-legacy-MacCatalyst vsdrops gist

View dotnet iOS-MacCatalayst API diff

• dotnet-macCatiOS vsdrops gist

API & Generator diff

ℹ️ API Diff (from PR only) (please review changes)
✅ Generator Diff (only version changes)

GitHub pages

Results can be found in the following github pages (it might take some time to publish):

• Test results
• API diff
• API & Generator diff

Test results

2 tests failed, 95 tests passed.

Failed tests

• monotouch-test/Mac [dotnet]/Debug [dotnet]: Failed (Test run failed.
  Tests run: 2539 Passed: 2415 Inconclusive: 10 Failed: 1 Ignored: 123)
• monotouch-test/Mac Catalyst [dotnet]/Debug [dotnet]: Failed (Tests run: 2704 Passed: 2502 Inconclusive: 35 Failed: 1 Ignored: 201)

Pipeline on Agent XAMBOT-1108.BigSur'
Merge 45754dd into 42fcb4f

[mandel-macaque]

Created an issue to track that, but it works in one config and not the others https://github.com/xamarin/maccore/issues/2525