Assert compiling dotnet/runtime in EmitConversions

[jaredpar]

When compiling dotnet/runtime with the latest compiler we get an assert in EmitConversions.cs

roslyn/src/Compilers/CSharp/Portable/CodeGen/EmitConversion.cs

Lines 156 to 159 in 3f192dc

	Debug.Assert(
	(toPredefTypeKind == Microsoft.Cci.PrimitiveTypeCode.IntPtr || toPredefTypeKind == Microsoft.Cci.PrimitiveTypeCode.UIntPtr) && !toType.IsNativeIntegerWrapperType ||
	toPredefTypeKind == Microsoft.Cci.PrimitiveTypeCode.Pointer ||
	toPredefTypeKind == Microsoft.Cci.PrimitiveTypeCode.FunctionPointer);

The assert occurs because the toPredefTypeKind is Int64.

The method which is causing the assert failure is here: https://github.com/dotnet/runtime/blob/f9ebd42d05ca88f086d472832487fbccfc7fe4ac/src/coreclr/tools/aot/ILCompiler.ReadyToRun/JitInterface/CorInfoImpl.ReadyToRun.cs#L2715

Found while digging into dotnet/runtime#82467