Remove dependency on xunit.analyzers

[dluc]

Motivation and Context

SK package should not depend on analyzers. Looks like xunit.analyzers pkg is somehow differently and the XML needed wasn't added automatically like other analyzers.

Description

Edit Directory.Packages.props and remove xunit.analyzers dependency from the nuget. I also noticed a couple of duplicate files left over from a bad merge (a folder rename), the PR takes care of deleting them.

[dluc]

Before:

After:

[dluc]

@timlaverty recently we renamed the folder SemanticKernel.Test to SemanticKernel.UnitTests and due to how some PRs got merged, the files ended up being duplicated

• dotnet/src/SemanticKernel.Test/Memory/Collections/MinHeapTests.cs [old orphan copy, unused]

• dotnet/src/SemanticKernel.UnitTests/Memory/Collections/MinHeapTests.cs

• dotnet/src/SemanticKernel.Test/Memory/Collections/TopNCollectionTests.cs [old orphan copy, unused]

• dotnet/src/SemanticKernel.UnitTests/Memory/Collections/TopNCollectionTests.cs

[dmytrostruk]

I removed obsolete unit-tests in previous PR as well: https://github.com/microsoft/semantic-kernel/pull/110