This takes the diff we have for our patched PostgreSQL 17 tools and
backports it to the PostgreSQL 16 tools.

The commands below were ran to do this:

  git checkout REL_17_10 # In the PostgreSQL repo

  git checkout -b fetools_17_10 main
  rm -r fetools/pg17
  tools/copy_fetools.sh path/to/pg 17
  git add fetools/pg17
  git commit -m REL_17_10
  git checkout pg16
  git diff fetools_17_10 main --relative=fetools/pg17 | git apply -3 --directory=fetools/pg16

The conflicts needed to be solved were minor.

Since we will need more frontend sepcific code to support PostgreSQL 16,
namely the error handling for the JSON parser, we may as well clean up
the pg_tde_fe.c and create a proper C file which we can compile and link
to.

Apparently PostgreSQL 17 moved some output from stdout to stderr.

Before PostgreSQL 17 pg_rewind did not support in-place tablesapces so
we should just skip those tests on PostgreSQL 16.

Before PostgreSQL 17 the default table access method only mattered when
creating tables, and was not relevant when running ALTER TABLE so there
was no SET ACCESS METHOD DEFAULT.

While doing this we also remove the unnecessary DROP TABLE commands,
which would have added more conditionals on the version, since we
already test DROP TABLE in other places and we remove the whole cluster
anyway.

It is a bit unclear if these test case should even exist in the first
place as we also test this in our pg_regress tests. The pg_regress tests
will be fixed to support PostgreSQL 16 in a later commit.

…ess method

Before PostgreSQL 17 the default table access method only mattered when
creating tables, and was not relevant when running ALTER TABLE so there
was no SET ACCESS METHOD DEFAULT.

…d tables

Before PostgreSQL 17 it was not possible to set the access method on
paritioned tables.