Reflection: ProtocolTypeRefs now store a mangled name

This is better for field metadata lookups. Clients that want the
module name and decl name can demangle, just like they do with
NominalTypeRefs.

lib/RemoteAST/RemoteAST.cpp

@@ -246,7 +246,9 @@ public:
     return FunctionType::get(input, output, einfo);
   }
 
-  Type createProtocolType(StringRef moduleName, StringRef protocolName) {
+  Type createProtocolType(StringRef mangledName,
+                          StringRef moduleName,
+                          StringRef protocolName) {
     auto module = Ctx.getModuleByName(moduleName);
     if (!module) return Type();