Make ext/shmop/tests/gh14537.phpt more resilient (GH-15985)

The actual problem is our `shmget()` implementation which does not care
to set `errno` appropriately; that should be fixed, although mapping
the error conditions to those specified by POSIX might be hard.

For now, we only make the test case more resilient by ignoring the
exact error; "No error" doesn't make sense anyway.

Author: cmb69

ext/shmop/tests/gh14537.phpt

@@ -23,5 +23,5 @@ var_dump($shm_id2);
 object(Shmop)#1 (0) {
 }
 
-Warning: shmop_open(): Unable to attach or create shared memory segment "No error" in %s on line %d
+Warning: shmop_open(): Unable to attach or create shared memory segment "%s" in %s on line %d
 bool(false)