Harmonize function parameter names for Postgres 18.

Make sure that function declarations use names that exactly match the
corresponding names from function definitions in a few places.  These
inconsistencies were all introduced during Postgres 18 development.

This commit was written with help from clang-tidy, by mechanically
applying the same rules as similar clean-up commits (the earliest such
commit was commit 035ce1fe).

src/test/modules/oauth_validator/fail_validator.c

@@ -22,7 +22,7 @@ PG_MODULE_MAGIC;
 static bool fail_token(const ValidatorModuleState *state,
 					   const char *token,
 					   const char *role,
-					   ValidatorModuleResult *result);
+					   ValidatorModuleResult *res);
 
 /* Callback implementations (we only need the main one) */
 static const OAuthValidatorCallbacks validator_callbacks = {

src/test/modules/oauth_validator/magic_validator.c

@@ -23,7 +23,7 @@ PG_MODULE_MAGIC;
 static bool validate_token(const ValidatorModuleState *state,
 						   const char *token,
 						   const char *role,
-						   ValidatorModuleResult *result);
+						   ValidatorModuleResult *res);
 
 /* Callback implementations (we only need the main one) */
 static const OAuthValidatorCallbacks validator_callbacks = {

src/test/modules/oauth_validator/validator.c

@@ -26,7 +26,7 @@ static void validator_shutdown(ValidatorModuleState *state);
 static bool validate_token(const ValidatorModuleState *state,
 						   const char *token,
 						   const char *role,
-						   ValidatorModuleResult *result);
+						   ValidatorModuleResult *res);
 
 /* Callback implementations (exercise all three) */
 static const OAuthValidatorCallbacks validator_callbacks = {