pgsql: Remove duplicative polygon SP-GiST sequencing test.

Remove duplicative polygon SP-GiST sequencing test.

Code coverage comparisons confirm that the tests using
quad_poly_tbl_ord_seq1/quad_poly_tbl_ord_idx1 hit no code
paths not also covered by the similar tests using
quad_poly_tbl_ord_seq2/quad_poly_tbl_ord_idx2. Since these
test cases are pretty expensive, they need to contribute more
than zero benefit.

In passing, make quad_poly_tbl_ord_seq2 a temp table, since
there seems little reason to keep it around after the test.

Discussion: https://postgr.es/m/735.1554935715@sss.pgh.pa.us

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/4aaa3b5cf1c33d713b8eefa3612a9112cbcf1074

Modified Files
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src/test/regress/expected/polygon.out | 27 +--------------------------
src/test/regress/expected/sanity_check.out | 2 --
src/test/regress/sql/polygon.sql | 21 +--------------------
3 files changed, 2 insertions(+), 48 deletions(-)