Add test for Swift array dynamic cast to NSObject

[lxbndr]

I am getting crash when trying to perform dynamic cast like this:

let anyArray: Any = [TestClass()]
let maybeObject = anyArray as? NSObject

Could not cast value of type 'TestFoundation.TestBridging.(unknown context at $7ff798798298).(unknown context at $7ff7987982a0).TestClass' (00007FF7988CC248) to 'Foundation.NSObject' (00007FFD7253A528). 

While it is possibly a bug in new dynamic casting in compiler, I think it is good to cover it with test already.

[lxbndr]

cc @compnerd @spevans
Could you please run a CI for this? I am going to add the test as xcfail, but first it would be good to see is it fails on Linux as well. Observing this on Windows.

[MaxDesiatov]

@swift-ci please test

[lxbndr]

So, it fails on Linux too

[MaxDesiatov]

Has anything changed substantially since the last push? Would you like me to retrigger CI for it?

[lxbndr]

@MaxDesiatov yes, please, that would be nice. Now it is expected-to-fail, so tests should pass. I would look into the reason of this behavior later.

[MaxDesiatov]

@swift-ci please test

[compnerd]

Thanks! If there is an SR, would be good to reference it.

[lxbndr]

I was wrong in test expectations. We should expect the value to be not nil. This doesn't affect the issue itself, as dynamic cast is still crashes.
@compnerd @MaxDesiatov Guys, could you please run CI one more time?

[MaxDesiatov]

@swift-ci please test

[spevans]

@swift-ci test linux

[lxbndr]

As the fix for this issue is merged, I am going to enable the test

[millenomi]

@swift-ci please test

[compnerd]

@swift-ci please test