Fixes initializer_list casting bug in PrettyPrint tests.

pretty_print_test.cpp

@@ -182,12 +182,13 @@ TestResults test_PrettyPrintWithATuple() {
 TestResults test_PrettyPrintWithAnInitializerList() {
   auto pretty_print = [](int i) {
     ostringstream os;
+    std::initializer_list<string> empty_initializer_list = {};
     switch (i) {
     case 1:
       PrettyPrint(os, {"one", "two", "three"});
       break;
     case 2:
-        PrettyPrint(os, (std::initializer_list<string>){});
+      PrettyPrint(os, empty_initializer_list);
       break;
     case 3:
       PrettyPrint(os, {1, 2, 3});