DeepClone in QuarkusTestExtension returns null

[alesj]

Custom JUnit5 extensions providing non-primitive test method arguments have issues wrt TCCL.
This is "solved" with DeepClone workaround.
But in our case this DeepClone impl returns null for a simple JDK Supplier instance:

• https://quarkusio.zulipchat.com/#narrow/stream/187030-users/topic/deep.20clone

[pepperbob]

Problems with cloning using XStream serialisation/deserialisation is also the cause of the issues #9677 and #9884

There is quite a list of limitations in the XStream-FAQ, e.g. My lambda expression is serialized to null!

[geoand]

Yeah, we'll have to address that