Drop MSTest doc that isn't VS specific

[Evangelink]

Relates to microsoft/testfx#4938

[prmerger-automator]

@Evangelink : Thanks for your contribution! The author(s) have been notified to review your proposed change.

[learn-build-service-prod]

Learn Build status updates of commit 513e39c:

✅ Validation status: passed

File	Status	Preview URL	Details
docs/test/using-microsoft-visualstudio-testtools-unittesting-members-in-unit-tests.md	✅Succeeded	n/a (file deleted or renamed)
docs/test/using-the-assert-classes.md	✅Succeeded	n/a (file deleted or renamed)

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[prmerger-automator]

PRMerger Results

Issue	Description
Deleted File(s)	This PR deletes Markdown or YAML files owned by another author, or json file(s). The pull request must contain a comment from the pull request author confirming that all the file deletions are intentional before the pull request can be merged.
File Change Percent	This PR contains file(s) with more than 30% file change.

[Evangelink]

@Mikejo5000 I am not sure how to do some redirection to the new doc on dotnet side.

[Mikejo5000]

@Evangelink No problem. I will add that! Actually, this PR will need to be on the private repo because of deletions. I will open that this morning.

[Mikejo5000]

@Evangelink Amaury, can you let me know the PR that adds this content to .NET? (I took a quick look, didn't see it.) That PR will need to be merged before I can merge a PR for deletion and redirection of these files. Or, are these deleted files redundant and can be removed without adding new content to dotnet docs?

[Court72]

@Evangelink No problem. I will add that! Actually, this PR will need to be on the private repo because of deletions. I will open that this morning.

@Mikejo5000 - I'll close this public PR for now. If you need it to be reopened, send an email to the
publicprs alias.

[Evangelink]

@Evangelink Amaury, can you let me know the PR that adds this content to .NET? (I took a quick look, didn't see it.) That PR will need to be merged before I can merge a PR for deletion and redirection of these files. Or, are these deleted files redundant and can be removed without adding new content to dotnet docs?

The PR were merged some time ago, here are the pages:

• https://learn.microsoft.com/dotnet/core/testing/unit-testing-mstest-writing-tests-attributes
• https://learn.microsoft.com/dotnet/core/testing/unit-testing-mstest-writing-tests-assertions

[Mikejo5000]

Thanks! The new PR to delete the files is here:
https://github.com/MicrosoftDocs/visualstudio-docs-pr/pull/13602