pgsql: Add pg_dump support for ALTER obj DEPENDS ON EXTENSION

Add pg_dump support for ALTER obj DEPENDS ON EXTENSION

pg_dump is oblivious to this kind of dependency, so they're lost on
dump/restores (and pg_upgrade).  Have pg_dump emit ALTER lines so that
they're preserved.  Add some pg_dump tests for the whole thing, also.

Reviewed-by: Tom Lane (offlist)
Reviewed-by: Ibrar Ahmed
Reviewed-by: Ahsan Hadi (who also reviewed commit 899a04f5ed61)
Discussion: https://postgr.es/m/20200217225333.GA30974@alvherre.pgsql

Branch
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REL_11_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/e70187c9b47cc1035a42196e62c4b5958f122a77

Modified Files
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src/bin/pg_dump/common.c                    |   1 +
src/bin/pg_dump/pg_dump.c                   | 107 +++++++++++++++++++++++++---
src/bin/pg_dump/pg_dump.h                   |   1 +
src/test/modules/test_pg_dump/t/001_base.pl |  32 +++++++++
4 files changed, 133 insertions(+), 8 deletions(-)