Fix plan instability in the new tuplesort test.
At least buildfarm member florican doesn't use a material node above a
sort in the mark/restore case. As material is not intended to be
tested with that query, disallow.
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/80ef34fc7075b37fc23f4ab714a5ce60f82400de
Modified Files
--------------
src/test/regress/expected/tuplesort.out | 10 +++++-----
src/test/regress/sql/tuplesort.sql | 1 +
2 files changed, 6 insertions(+), 5 deletions(-)