7856f2d83d only partially skipped writing
out destructors when they were invalid, ie. it skipped writing the decl
itself but not the records common to all decls. This would cause any
records on the destructor to be applied on the next serialized decl.
Make sure to skip serializing anything to do with the destructor when
it's invalid and does not have a class context.
Most invalid attributes are skipped from serialization entirely, but
custom attributes don't have their invalid bit set - the particular
custom attribute (eg. a property wrapper) is requested when needed and
skipped if invalid. Those checks can't set the invalid bit since the
attribute could be a different custom attribute (eg. a result builder).
When allowing errors any attribute could be on any decl, so don't verify
whether an attribute can appear on a decl. Note that these attributes
aren't serialized anyway since they'll be set to invalid during
typechecking and hence skipped.
