pgsql: Use palloc_object() and palloc_array() in more areas of the logi

Use palloc_object() and palloc_array() in more areas of the logical replication.

The idea is to encourage the use of newer routines across the tree, as
these offer stronger type-safety guarantees than raw palloc().

Similar work has been done in commits 1b105f9472bd, 0c3c5c3b06a3,
31d3847a37be, and 4f7dacc5b82a. This commit extends those changes to
more locations within src/backend/replication/logical/.

Author: Peter Smith <smithpb2250(at)gmail(dot)com>
Reviewed-by: Chao Li <li(dot)evan(dot)chao(at)gmail(dot)com>
Reviewed-by: Hayato Kuroda <kuroda(dot)hayato(at)fujitsu(dot)com>
Reviewed-by: Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>
Discussion: https://postgr.es/m/CAHut+Pv4N7Vpxo18+NAR1r9RGvR8b0BtwTkoeCE2PfFoXgmR6A@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/50ea4e09b6c2331b4cc6434fa12b43bc62de682c

Modified Files
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src/backend/replication/logical/proto.c | 2 +-
src/backend/replication/logical/reorderbuffer.c | 8 ++++----
src/backend/replication/logical/snapbuild.c | 7 ++++---
src/backend/replication/logical/tablesync.c | 4 ++--
src/backend/replication/logical/worker.c | 14 +++++++-------
5 files changed, 18 insertions(+), 17 deletions(-)