pgsql: tableam: Add pg_dump support.

tableam: Add pg_dump support.

This adds pg_dump support for table AMs in a similar manner to how
tablespaces are handled. That is, instead of specifying the AM for
every CREATE TABLE etc, emit SET default_table_access_method
statements. That makes it easier to change the AM for all/most tables
in a dump, and allows restore to succeed even if some AM is not
available.

This increases the dump archive version, as a tables/matview's AM
needs to be tracked therein.

Author: Dimitri Dolgov, Andres Freund
Discussion:
    https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de
    https://postgr.es/m/20190304234700.w5tmhducs5wxgzls@alap3.anarazel.de

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/3b925e905de3204ffef64fa4d53dd7bbac1a143f

Modified Files
--------------
src/bin/pg_dump/pg_backup_archiver.c | 57 +++++++++++++++++++++++++++++++++-
src/bin/pg_dump/pg_backup_archiver.h |  6 +++-
src/bin/pg_dump/pg_dump.c            | 22 +++++++++++--
src/bin/pg_dump/pg_dump.h            |  1 +
src/bin/pg_dump/t/002_pg_dump.pl     | 60 ++++++++++++++++++++++++++++++++++++
5 files changed, 142 insertions(+), 4 deletions(-)