jsauthority: re-enable JIT

seems to work with mozjs52

src/polkitbackend/polkitbackendjsauthority.cpp

@@ -458,13 +458,10 @@ polkit_backend_js_authority_constructed (GObject *object)
   if (!JS::InitSelfHostedCode (authority->priv->cx))
     goto fail;
 
-  /* TODO: JIT'ing doesn't work will with killing runaway scripts... I think
-   *       this is just a SpiderMonkey bug. So disable the JIT for now.
-   */
   JS::ContextOptionsRef (authority->priv->cx)
-      .setIon (FALSE)
-      .setBaseline (FALSE)
-      .setAsmJS (FALSE);
+      .setIon (TRUE)
+      .setBaseline (TRUE)
+      .setAsmJS (TRUE);
   JS::SetWarningReporter(authority->priv->cx, report_error);
   JS_SetContextPrivate (authority->priv->cx, authority);