Bug 35702: Fetch biblios at once and loop

Bug 35702: Fetch biblios at once and loop

Test plan:
prove -v t/db_dependent/Authority/Merge.t

Signed-off-by: David Nind <david@davidnind.com>
Amended-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Replace $biblio->id with $biblio->biblionumber

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit 1847e2ab565243a9e8fcaf8ddbfe48136041e61b)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>