Native AOT: marshal empty array as non-null

[sbomer]

Fixes a discrepancy where coreclr marshals empty blittable arrays as non-null, but native AOT marshals them as null. With the fix, native AOT marshals them as non-null.

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[MichalStrehovsky]

Maybe this is fixing #81674? I don't know if there's more issues after this one, but the error message in the issue looks suspiciously related:

============ [CStyle_Array_Int_InOut_ZeroLength] ============
[CStyle_Array_Int_InOut_ZeroLength] Error: parameter actual is NULL

Might be worth removing the ActiveIssue/issues.targets entries to see if the test can pass now.

[sbomer]

I don't know if there's more issues after this one, but the error message in the issue looks suspiciously related:

Tried enabling that test - it looks like we get past that particular error, but then it fails later in TestMarshalByVal_Out.