MDL-53623 behat: catch expection if failed to trigger event

Inline editing element might hide before
event is triggred, so don't trigger exception
if exception happens

lib/behat/form_field/behat_form_select.php

@@ -76,7 +76,12 @@ public function set_value($value) {
             $browser = \Moodle\BehatExtension\Driver\MoodleSelenium2Driver::getBrowser();
             if (!$singleselect && ($browser == 'phantomjs')) {
                 $script = "Syn.trigger('change', {}, {{ELEMENT}})";
-                $this->session->getDriver()->triggerSynScript($this->field->getXpath(), $script);
+                try {
+                    $this->session->getDriver()->triggerSynScript($this->field->getXpath(), $script);
+                } catch (Exception $e) {
+                    // No need to do anything if element has been removed by JS.
+                    // This is possible when inline editing element is used.
+                }
             }
             $this->session->wait(behat_base::TIMEOUT * 1000, behat_base::PAGE_READY_JS);
         }