pgsql: Fix print of Path nodes when using OPTIMIZER_DEBUG

Fix print of Path nodes when using OPTIMIZER_DEBUG

GatherMergePath (introduced in 10) and CustomPath (introduced in 9.5)
have gone missing.  The order of the Path nodes was inconsistent with
what is listed in nodes.h, so make the order consistent at the same time
to ease future checks and additions.

Author: Sawada Masahiko
Reviewed-by: Michael Paquier
Discussion: https://postgr.es/m/CAD21AoBQMLoc=ohH-oocuAPsELrmk8_EsRJjOyR8FQLZkbE0wA@mail.gmail.com

Branch
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REL_11_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/bc62aef53d686b282f164277da0f2405a4fd0ac3

Modified Files
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src/backend/optimizer/path/allpaths.c | 31 +++++++++++++++++++------------
1 file changed, 19 insertions(+), 12 deletions(-)