Fix disableAutoFetch regression in the generic viewer

After PR 5263, setting `disableAutoFetch = true` in the generic viewer no longer works correctly, since the entire file loads even with `disableStream = true`.

src/core/worker.js

@@ -138,7 +138,7 @@ var WorkerMessageHandler = PDFJS.WorkerMessageHandler = {
           }
         },
 
-        onProgressiveData: PDFJS.disableStream ? null :
+        onProgressiveData: source.disableStream ? null :
             function onProgressiveData(chunk) {
           if (!pdfManager) {
             cachedChunks.push(chunk);

src/display/api.js

@@ -1076,6 +1076,7 @@ var WorkerTransport = (function WorkerTransportClosure() {
 
     fetchDocument: function WorkerTransport_fetchDocument(source) {
       source.disableAutoFetch = PDFJS.disableAutoFetch;
+      source.disableStream = PDFJS.disableStream;
       source.chunkedViewerLoading = !!this.pdfDataRangeTransport;
       this.messageHandler.send('GetDocRequest', {
         source: source,