Replace some %llu remnants in the tree

Hi all,

While hacking a different patch, I've noticed that a couple of %llu
did not get the PRIu64 call in the AIO code, and I don't see why we
could not switch them. These have been introduced in commits that got
into the tree after Peter's 15a79c73111f.

A couple remain even after the attached, which have been left off by
Peter for the same reasons as the ones I am guessing here:
- launch_backend.c for paramHandle, does not seem worth it.
- ecpglib/execute.c, when storing some input, which does not seem
worth bothering either.
- reconstruct.c, offset handling.
- pg_backup_tar.c, ftello() result and some consistency with the
surroundings.
- pg_verifybackup.c and astreamer_verify.c, for Sizes.

That's not necessarily mandatory for v18, for sure, but as this is new
code we could as well clean it up before forking the next stable
branch.

Comments or opinions?
--
Michael