pgcrypto: Remove explicit hex encoding/decoding from tests

This was from before the hex format was available in bytea.  Now we
can remove the extra explicit encoding/decoding calls and rely on the
default output format.

Discussion: https://www.postgresql.org/message-id/flat/17dcb4f7-7ac1-e2b6-d5f7-2dfba06cd9ee%40enterprisedb.com

contrib/pgcrypto/expected/init.out

@@ -2,21 +2,6 @@
 -- init pgcrypto
 --
 CREATE EXTENSION pgcrypto;
--- ensure consistent test output regardless of the default bytea format
-SET bytea_output TO escape;
--- check for encoding fn's
-SELECT encode('foo', 'hex');
- encode 
---------
- 666f6f
-(1 row)
-
-SELECT decode('666f6f', 'hex');
- decode 
---------
- foo
-(1 row)
-
 -- check error handling
 select gen_salt('foo');
 ERROR:  gen_salt: Unknown salt algorithm