A sample carrying the HealthLog origin marker was always dropped from an
export import. After a move to a new instance without a backup, the
export is how the mirrored values come back, and every one of them was
silently left out. A marked sample now counts as written by HealthLog
only when its HKExternalUUID names a row of this account of the same
kind, deleted rows included; a marked cycle sample only when the
account holds a day-log on its day. Every other marked sample is
imported, and still meets the manual-value match. A correlation's own
HKExternalUUID now covers records that carry none.
The fixture is invented, in the shape Apple's DTD documents, and says so in its
header and its file name. It shows the parser reads a file laid out like an
export; it cannot show that Apple writes a custom metadata key verbatim.