pgsql: Simplify abbreviated key hashing during cardinality estimation

Simplify abbreviated key hashing during cardinality estimation

In the wake of commit 2a600a93c, Datums are 64-bit values, so
we no longer need to fold the abbreviated key to 32 bits before
hashing. Instead, use murmurhash64(), which is simpler and avoids
a function call. Also replace hash_uint32() with murmurhash32()
in related places.

Author: Aleksander Alekseev <aleksander(at)tigerdata(dot)com>
Suggested-by: John Naylor <johncnaylorls(at)gmail(dot)com>
Reviewed-by: Aditya Gollamudi <adigollamudi(at)gmail(dot)com> (earlier version)
Reviewed-by: Michael Paquier <michael(at)paquier(dot)xyz> (earlier version)
Discussion: https://postgr.es/m/CAJ7c6TMPhDRQMmkUHPv8oOK97B1mR8NRS61DgjpdaZUPAwaeZQ%40mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/d39fda1cc404834781458376173e5293f870e83a

Modified Files
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src/backend/utils/adt/bytea.c | 9 ++-------
src/backend/utils/adt/network.c | 9 ++-------
src/backend/utils/adt/numeric.c | 8 ++------
src/backend/utils/adt/uuid.c | 9 ++-------
src/backend/utils/adt/varlena.c | 9 ++-------
5 files changed, 10 insertions(+), 34 deletions(-)