Add missing fields to _outConstraint()

As of 89779524, check constraints can
be declared invalid.  But that patch didn't update _outConstraint() to
also show the relevant struct fields (which were only applicable to
foreign keys before that).  This currently only affects debugging
output, so no impact in practice.

src/backend/nodes/outfuncs.c

@@ -3688,6 +3688,8 @@ _outConstraint(StringInfo str, const Constraint *node)
 			WRITE_BOOL_FIELD(is_no_inherit);
 			WRITE_NODE_FIELD(raw_expr);
 			WRITE_STRING_FIELD(cooked_expr);
+			WRITE_BOOL_FIELD(skip_validation);
+			WRITE_BOOL_FIELD(initially_valid);
 			break;
 
 		case CONSTR_PRIMARY: