This commit significantly increases test coverage of geo_ops.c, adding
tests for various issues addressed by 2e2a392d (which went undetected
for a long time, at least partially due to not being covered).

This also removes alternative results expecting -0 on some platforms.
Instead the functions are should return the same results everywhere,
transforming -0 to 0 if needed.

The tests are added to geometric.sql file, sorted by the left hand side
of the operators. There are many cross datatype operators, so this seems
like the best solution.

Author: Emre Hasegeli
Reviewed-by: Tomas Vondra

Discussion: https://www.postgresql.org/message-id/CAE2gYzxF7-5djV6-cEvqQu-fNsnt%3DEqbOURx7ZDg%2BVv6ZMTWbg%40mail.gmail.com