pgsql: Remove contrib/jsonb_plpython's tests for infinity and NaN conve

Remove contrib/jsonb_plpython's tests for infinity and NaN conversions.

These tests don't work reliably with pre-2.6 Python versions, since
Python code like float('inf') was not guaranteed to work before that,
even granting an IEEE-compliant platform.

Since there's no explicit handling of these cases in jsonb_plpython,
we're not adding any real code coverage by testing them, and thus
it doesn't seem to make sense to go to any great lengths to work
around the test instability.

Discussion: https://postgr.es/m/E1f1AMU-00031c-9N@gemulon.postgresql.org

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/6278a2a262b63faaf47eb2371f6bcb5b6e3ff118

Modified Files
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contrib/jsonb_plpython/expected/jsonb_plpython.out | 40 ----------------------
contrib/jsonb_plpython/sql/jsonb_plpython.sql | 35 -------------------
2 files changed, 75 deletions(-)