Add test for literal-only static function.

Author: kevinpschaaf

test/unit/property-effects.html

@@ -1924,12 +1924,14 @@
       _template: html`
         <div>[[hostProp]]</div>    <!-- host prop -->
         <div>[[noDeps()]]</div>    <!-- method with no deps -->
+        <div>[[literalDeps('hi')]]</div>  <!-- method with literal deps -->
         <div>[[dynamicFn()]]</div> <!-- dynamic function with no deps -->
         <div>[[dynamicFnWithDep(hostProp)]]</div>  <!-- dynamic function with deps -->
         <template is="dom-repeat" items="[0]" as="instProp">
           <div>[[instProp]]</div>  <!-- instance prop -->
           <div>[[hostProp]]</div>  <!-- nested host prop -->
           <div>[[noDeps()]]</div>  <!-- nested method with no deps -->
+          <div>[[literalDeps('hi')]]</div>  <!-- method with literal deps -->
           <div>[[dynamicFn()]]</div> <!-- dynamic function with no deps -->
           <div>[[dynamicFnWithDep(hostProp)]]</div>  <!-- dynamic function with deps -->
         </template>