pgsql: Reduce duration of stats_ext regression tests

Reduce duration of stats_ext regression tests

The regression tests of extended statistics were taking a fair amount of
time, due to using fairly large data sets with a couple thousand rows.
So far this was fine, but with tests for statistics on expressions the
duration would get a bit excessive.  So reduce the size of some of the
tests that will be used to test expressions, to keep the duration under
control.  Done in a separate commit before adding the statistics on
expressions, to make it clear which estimates are expected to change.

Author: Tomas Vondra
Discussion: https://postgr.es/m/ad7891d2-e90c-b446-9fe2-7419143847d7%40enterprisedb.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/98376c18f12e562421b5c77e619248e8b7aae3c6

Modified Files
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src/test/regress/expected/stats_ext.out | 42 ++++++++++++++++-----------------
src/test/regress/sql/stats_ext.sql      |  8 +++----
2 files changed, 25 insertions(+), 25 deletions(-)