pgsql: Fix omission of locations in outfuncs/readfuncs partitioning nod

Fix omission of locations in outfuncs/readfuncs partitioning node support.

We could have limped along without this for v10, which was my intention
when I annotated the bug in commit 76a3df6e5. But consensus is that it's
better to fix it now and take the cost of a post-beta1 initdb (which is
needed because these node types are stored in pg_class.relpartbound).

Since we're forcing initdb anyway, take the opportunity to make the node
type identification strings match the node struct names, instead of being
randomly different from them.

Discussion: https://postgr.es/m/E1dFBEX-0004wt-8t@gemulon.postgresql.org

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/80f583ffe930b21d6e5c47be4342356e57851a9a

Modified Files
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src/backend/nodes/outfuncs.c | 10 +++++-----
src/backend/nodes/readfuncs.c | 10 ++++------
src/include/catalog/catversion.h | 2 +-
3 files changed, 10 insertions(+), 12 deletions(-)