[php] Ensure _runme.php calls check::done()

This function doesn't do anything currently so these missing calls are a
latent issue.  It could be used for e.g. memory leak checking in the
future though, and it's potentially a useful place to add code when
debugging.

Examples/test-suite/php/threads_exception_runme.php

@@ -40,3 +40,5 @@ foreach (Array(1,2,3,4) as $i) {
     } catch (Exception $e) {
     }
 }
+
+check::done();