Add crashtest.

content/base/crashtests/308120-1.xul

@@ -0,0 +1,3 @@
+<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul" onload="var button=document.getElementsByTagName('button')[0]; try { button.appendChild(document.getAnonymousNodes(button)[0]); } catch(e) { }">
+  <button/>
+</window>

content/base/crashtests/crashtests.list

@@ -1,3 +1,4 @@
+load 308120-1.xul
 load 325730-1.html
 load 326618-1.html
 load 326646-1.html