pgsql: Avoid naming conflict between transactions.sql and namespace.sql

Avoid naming conflict between transactions.sql and namespace.sql.

Commits 681d9e462 et al added a test case in namespace.sql that
implicitly relied on there not being a table "public.abc".
However, the concurrently-run transactions.sql test creates precisely
such a table, so with the right timing you'd get a failure.
Creating a table named as generically as "abc" in a common schema
seems like bad practice, so fix this by changing the name of
transactions.sql's table.  (Compare 2cf8c7aa4.)

Marina Polyakova

Discussion: https://postgr.es/m/80d0201636665d82185942e7112257b4@postgrespro.ru

Branch
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REL_15_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/89f5eb26f6b9b2739aacf53676bfa0eee7be421a

Modified Files
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src/test/regress/expected/transactions.out | 76 +++++++++++++++---------------
src/test/regress/sql/transactions.sql      | 64 ++++++++++++-------------
2 files changed, 70 insertions(+), 70 deletions(-)