PHPC-441: Skip (xfail) these tests while the ticket is being worked on

Author: bjori

tests/server/server-executeCommand-002.phpt

@@ -1,5 +1,7 @@
 --TEST--
 MongoDB\Driver\Server::executeCommand() takes a read preference
+--XFAIL--
+See PHPC-441: slaveOk bit not set when using hint to query a secondary directly
 --SKIPIF--
 <?php require __DIR__ . "/../utils/basic-skipif.inc"; NEEDS("REPLICASET"); ?>
 --FILE--

tests/server/server-executeQuery-005.phpt

@@ -1,5 +1,7 @@
 --TEST--
 MongoDB\Driver\Server::executeQuery() takes a read preference
+--XFAIL--
+See PHPC-441: slaveOk bit not set when using hint to query a secondary directly
 --SKIPIF--
 <?php require __DIR__ . "/../utils/basic-skipif.inc"; NEEDS("REPLICASET"); ?>
 --FILE--