Lazy objects: Update class constants earlier

If a lazy object is created for a class whose constants can not be updated, then
we have created an instance of a non-instantiable class. Thi

Lazy objects: Update class constants earlier

If a lazy object is created for a class whose constants can not be updated, then
we have created an instance of a non-instantiable class. This breaks the
expectations of clone.

Here I ensure that a class has its constants updated before creating a lazy
instance of it.

Fixes OSS-Fuzz #71407
Closes GH-15856

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