Lower memory impact of objects in exceptions
Currently, the exceptions store two sides (handle + pointer) of the object fields, while the second side is only used when the data is read out. Also, having this second side in the exception data stops the exception fields from being read in parallel as there's data race otherwise.
Also, at some cases other users of sivelkiria::kernel::object_value and its subclasses might not need the second side or benifit from moving it out from the class fields as well. For example, the invocations don't use second side at all when processed by the kernel itself.
Need to split object_value (and exception_value?) somehow, so that they only store for the long time the values that are actually being used. Process these values in parallel where possible.