[iOS] Reenable skipped StructureToPtr tests

[steveisok]

As a result of #73013 landing, the skipped StructureToPtr tests can be enabled.

Contributes to #73008

[ghost]

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Issue Details

---

As a result of #73013 landing, the skipped StructureToPtr tests can be enabled.

Contributes to #73008

Author:	steveisok
Assignees:	-
Labels:	area-System.Runtime.InteropServices
Milestone:	-

[steveisok]

/azp run runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[steveisok]

@vargaz These are still failing because it's trying to JIT:

runtime/src/libraries/System.Runtime.InteropServices/tests/System.Runtime.InteropServices.UnitTests/System/Runtime/InteropServices/Marshal/PtrToStructureTests.cs

Lines 153 to 160 in aac729f

	public unsafe void PtrToStructure_GenericLayoutClass_Generic()
	{
	int i = 42;
	IntPtr ptr = (IntPtr)(&i);
	SequentialGenericClass<int> obj = new SequentialGenericClass<int>();
	Marshal.PtrToStructure(ptr, obj);
	Assert.Equal(i, obj.field);
	}

runtime/src/libraries/System.Runtime.InteropServices/tests/System.Runtime.InteropServices.UnitTests/System/Runtime/InteropServices/Marshal/PtrToStructureTests.cs

Lines 164 to 171 in aac729f

	public unsafe void PtrToStructure_GenericLayoutClass()
	{
	int i = 42;
	IntPtr ptr = (IntPtr)(&i);
	SequentialGenericClass<int> obj = new SequentialGenericClass<int>();
	Marshal.PtrToStructure(ptr, (object)obj);
	Assert.Equal(i, obj.field);
	}

runtime/src/libraries/System.Runtime.InteropServices/tests/System.Runtime.InteropServices.UnitTests/System/Runtime/InteropServices/Marshal/StructureToPtrTests.cs

Lines 261 to 282 in aac729f

	public void StructureToPtr_Flat_And_Nested_NonBlittableStructure_Success()
	{
	MarshalAndDestroy(new NonBlittableStruct_Flat
	{
	del = null,
	b = 0x55,
	});
	MarshalAndDestroy(new NonBlittableStruct_Nested
	{
	s = { del = null },
	b = 0x55,
	});
	static unsafe void MarshalAndDestroy<T>(T value) where T : struct
	{
	int sizeof_T = Marshal.SizeOf<T>();
	void* ptr = stackalloc byte[sizeof_T];
	Marshal.StructureToPtr(value, (IntPtr)ptr, false);
	Marshal.DestroyStructure<T>((IntPtr)ptr);
	}
	}

[steveisok]

/azp run runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[steveisok]

@vargaz StructureToPtr_Flat_And_Nested_NonBlittableStructure_Success is still failing. I'm going to skip that test and move this PR forward.