[src/core/worker.js] Remove a useless Promise handler from the pdfManagerReady function

Looking carefully at this code, you'll notice that the `loadDocument` function has no less than *three* Promise handling functions. This obviously makes no sense, since a Promise can only have one resolve and one reject handler.

Hence the final `onFailure`-case is unreachable, which only serves to add confusion when reading the code. Note that this code has been re-factored more than once over the years, but it seems as if this may even have been incorrect already in PR 3310 (and no-one have noticed for seven years :-).

src/core/worker.js

@@ -371,25 +371,21 @@ class WorkerMessageHandler {
       function pdfManagerReady() {
         ensureNotTerminated();
 
-        loadDocument(false).then(
+        loadDocument(false).then(onSuccess, function (reason) {
-          onSuccess,
+          ensureNotTerminated();
-          function loadFailure(ex) {
+
+          // Try again with recoveryMode == true
+          if (!(reason instanceof XRefParseException)) {
+            onFailure(reason);
+            return;
+          }
+          pdfManager.requestLoadedStream();
+          pdfManager.onLoadedStream().then(function () {
             ensureNotTerminated();
 
-            // Try again with recoveryMode == true
+            loadDocument(true).then(onSuccess, onFailure);
-            if (!(ex instanceof XRefParseException)) {
+          });
-              onFailure(ex);
+        });
-              return;
-            }
-            pdfManager.requestLoadedStream();
-            pdfManager.onLoadedStream().then(function () {
-              ensureNotTerminated();
-
-              loadDocument(true).then(onSuccess, onFailure);
-            });
-          },
-          onFailure
-        );
       }
 
       ensureNotTerminated();