refactor($compile): simplify controllersBoundTransclude check

no measurable perf difference, but the code more simple and minifies better

Author: IgorMinar

src/ng/compile.js

@@ -1643,7 +1643,7 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
           var transcludeControllers;
 
           // no scope passed
-          if (arguments.length < 2) {
+          if (!cloneAttachFn) {
             cloneAttachFn = scope;
             scope = undefined;
           }