It was getting in the way of backporting commit 9b1b9446f5 from PostgreSQL,
which added an '#include "storage/lock.h"' to resowner.h, forming a cycle.

The include was only needed for the decalaration of awaitedOwner global
variable. Replace "ResourceOwner" with the equivalent "struct
ResourceOwnerData *" to avoid it.

This revealed a bunch of other files that were relying on resowner.h
being indirectly included through lock.h. Include resowner.h directly
in those files.

The ResPortalIncrement.owner field was not used for anything, so instead
of including resowner.h in that file, just remove the field that needed
it.