ntoskrnl: Allow running user APC inside the device manager loop.

dlls/ntoskrnl.exe/ntoskrnl.c

@@ -244,11 +244,16 @@ NTSTATUS CDECL wine_ntoskrnl_main_loop( HANDLE stop_event )
             /* restart with larger buffer */
             break;
         case STATUS_PENDING:
-            if (WaitForMultipleObjects( 2, handles, FALSE, INFINITE ) == WAIT_OBJECT_0)
+            for (;;)
+            {
+                DWORD ret = WaitForMultipleObjectsEx( 2, handles, FALSE, INFINITE, TRUE );
+                if (ret == WAIT_OBJECT_0)
                 {
                     HeapFree( GetProcessHeap(), 0, in_buff );
                     return STATUS_SUCCESS;
                 }
+                if (ret != WAIT_IO_COMPLETION) break;
+            }
             break;
         }
     }