Fix expected output for spoly regression tests.

Author: esabol

expected/poly.out

@@ -350,7 +350,7 @@ LINE 1: SELECT spoly '{(10d,0d),(10d,1d)}';
 SELECT spoly(ARRAY[1.0, 2.0, 3.0, 4.0, 5.0]);
 ERROR:  spherepoly_rad: invalid number of arguments (must be even and >= 6)
 SELECT spoly(ARRAY[1.0, 2.0, 3.0, NULL, 5.0, 6.0]);
-ERROR:  spherepoly_rad: invalid array has null values
+ERROR:  spherepoly_rad: input array is invalid because it has null values
 SELECT spoly(ARRAY[]::float8[]);
 ERROR:  spherepoly_rad: invalid number of arguments (must be even and >= 6)
 SELECT spoly(NULL::float8[]);
@@ -362,7 +362,7 @@ SELECT spoly(NULL::float8[]);
 SELECT spoly_deg(ARRAY[1.0, 2.0, 3.0, 4.0, 5.0]);
 ERROR:  spherepoly_deg: invalid number of arguments (must be even and >= 6)
 SELECT spoly_deg(ARRAY[1.0, 2.0, 3.0, NULL, 5.0, 6.0]);
-ERROR:  spherepoly_deg: invalid array has null values
+ERROR:  spherepoly_deg: input array is invalid because it has null values
 SELECT spoly_deg(ARRAY[]::float8[]);
 ERROR:  spherepoly_deg: invalid number of arguments (must be even and >= 6)
 SELECT spoly_deg(NULL::float8[]);