Switch all `[DataTestMethod]` to `[TestMethod]`

[Youssef1313]

See microsoft/testfx#4166

[codeofdusk]

Sounds reasonable. Are you willing to submit a PR?

[marcelwgn]

I think this issue has been addressed right? (except for one commented out occurence)

[Youssef1313]

Yes. And I'm avoiding now the commented out occurrence in #1093.

[codeofdusk]

We've typically kept issues open until the associated PR is included in a release. If and when we release next, this issue will be closed out.