[EFL][GTK][WKTR] Regression(r145231): Undefined symbol in libTestRunnerInjectedBundle.so
https://bugs.webkit.org/show_bug.cgi?id=111970

Reviewed by Chris Fleizach.

Provide dummy implementation for AccessibilityUIElement::supportedActions() in ATK
or libTestRunnerInjectedBundle.so cannot be loaded in EFL / GTK otherwise, due to
undefined symbol.

* WebKitTestRunner/InjectedBundle/atk/AccessibilityUIElementAtk.cpp:
(WTR::AccessibilityUIElement::supportedActions):
(WTR):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@145361 268f45cc-cd09-0410-ab3c-d52691b4dbfc