Add [Fact] attributes on TypeGeneratorTests

[trylek]

For now there's no functional change to the behavior of the tests,
I have just copied the bits to inject from Jeremy's example in his
pending PR.

Thanks

Tomas

Contributes to: #54512

[ghost]

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Issue Details

---

For now there's no functional change to the behavior of the tests,
I have just copied the bits to inject from Jeremy's example in his
pending PR.

Thanks

Tomas

Contributes to: #54512

Author:	trylek
Assignees:	-
Labels:	area-Infrastructure-coreclr
Milestone:	-

[trylek]

I have triggered a CoreCLR outerloop run but not the CI run as I believe all these tests are Pri1 so that they don't run in CI.

[trylek]

The arm / arm64 runs are pretty flaky these days but I have double-checked in the AzDO UI that none of the outstanding failures are related to the TypeGeneratorTests I'm modifying in this PR, merging in.