pgsql: refactor: Split tryAttachPartitionForeignKey()

refactor: Split tryAttachPartitionForeignKey()

Split tryAttachPartitionForeignKey() into three functions:
AttachPartitionForeignKey(), RemoveInheritedConstraint(), and
DropForeignKeyConstraintTriggers(), so they can be reused in some
subsequent patches for the NOT ENFORCED feature.

Author: Amul Sul <amul.sul@enterprisedb.com>
Reviewed-by: Alexandra Wang <alexandra.wang.oss@gmail.com>
Discussion: /messages/by-id/CAAJ_b962c5AcYW9KUt_R_ER5qs3fUGbe4az-SP-vuwPS-w-AGA@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/1d26c2d2c4b8d833a63ba403bc9313db2c091aa7

Modified Files
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src/backend/commands/tablecmds.c | 319 +++++++++++++++++++++++++--------------
1 file changed, 204 insertions(+), 115 deletions(-)