Fix NaN comparison in circle_same test

Fix NaN comparison in circle_same test

Commit c4c340088 changed geometric operators to use float4 and float8
functions, and handle NaN's in a better way. The circle sameness test
had a typo in the code which resulted in all comparisons with the left
circle having a NaN radius considered same.

  postgres=# select '<(0,0),NaN>'::circle ~= '<(0,0),1>'::circle;
  ?column?
  ----------
  t
  (1 row)

This fixes the sameness test to consider the radius of both the left
and right circle.

Backpatch to v12 where this was introduced.

Author: Ranier Vilela <ranier.vf@gmail.com>
Discussion: https://postgr.es/m/CAEudQAo8dK=yctg2ZzjJuzV4zgOPBxRU5+Kb+yatFiddtQk6Rw@mail.gmail.com
Backpatch-through: v12