urlmon: Do not fill stream buffer on every report_data, native doesn't.

dlls/urlmon/binding.c

diff --git a/dlls/urlmon/binding.c b/dlls/urlmon/binding.c
index 0de8a36..0ba4cdb 100644
--- a/dlls/urlmon/binding.c
+++ b/dlls/urlmon/binding.c
@@ -949,8 +949,6 @@
         This->request_locked = SUCCEEDED(hres);
     }
 
-    fill_stream_buffer(This->stream);
-
     IBindStatusCallback_OnDataAvailable(This->callback, bscf, progress,
             &formatetc, &This->stgmed);