pgsql: Fix failure-to-copy bug in commit 6f6b99d13.

Fix failure-to-copy bug in commit 6f6b99d13.

The previous coding of get_qual_for_list() was careful to copy everything
it was using from the input data structure. The new version missed
making a copy of pass-by-ref datum values that it's inserting into Consts.
This is not optional, however, as revealed by buildfarm failures on
machines running -DRELCACHE_FORCE_RELEASE: we're copying from a relcache
entry that could go away before the required lifespan of our output
expression. I'm pretty sure -DCLOBBER_CACHE_ALWAYS machines won't like
this either, but none of them have reported in yet.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/fdf87ed451ef1ccb710f4e65dddbc6da17e92ba7

Modified Files
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src/backend/catalog/partition.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)