pgsql: Dump more fields when dumping planner internal data structures.

Dump more fields when dumping planner internal data structures.

Commit 964d01ae9 marked a lot of fields as read_write_ignore
to stay consistent with what was dumped by the manually-maintained
outfuncs.c code. However, it seems that a pretty fair number
of those omissions were either flat-out oversights, or a shortcut
taken because hand-written code seemed like it'd be too much trouble.
Let's upgrade things where it seems to make sense to dump.

To do this, we need to add support to gen_node_support.pl and
outfuncs.c for variable-length arrays of Node pointers. That's
pretty straightforward given the model of the existing code
for arrays of scalars, but I found I needed to tighten the
type-recognizing regexes in gen_node_support.pl. (As they
stood, they mistook "foo **" for "foo *". Make sure they're
all fully anchored to prevent additional problems.)

The main thing left un-done here is that a lot of partitioning-related
structs are still not dumped, because they are bare structs not Nodes.
I'm not sure about the wisdom of that choice ... but changing it would
be fairly invasive, so it probably requires more justification than
just making planner node dumps more complete.

Discussion: https://postgr.es/m/1295668.1658258637@sss.pgh.pa.us

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/af119e08fd147e808927b1a4c9f091636d52eb45

Modified Files
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src/backend/nodes/gen_node_support.pl | 68 ++++++++++++++++++---------
src/backend/nodes/outfuncs.c | 28 +++++++++++
src/include/nodes/pathnodes.h | 88 +++++++++++++++++++----------------
3 files changed, 123 insertions(+), 61 deletions(-)