Prevent stack overflow in Attribute.cs

[leotsarev]

fixes #35784

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[teo-tsirpanis]

The comment is incorrect, but I'm not sure whether behavior needs to change. An Attribute containing an Attribute does not necessarily lead to stack overflows; it does only if there is a cycle, and if there is, a custom override of the Equals method looks better.

Are there any real-world examples that would need this fix?

[leotsarev]

Real life example was from my code (see original bug).

[leotsarev]

I agree that custom Equals override should be better, but I think that framework should show correct error.