ntdll: Support loading binaries that start inside the DOS area.

dlls/ntdll/virtual.c

@@ -1593,6 +1593,8 @@ void virtual_init(void)
         {
             preload_reserve_start = (void *)start;
             preload_reserve_end = (void *)end;
+            /* some apps start inside the DOS area */
+            address_space_start = min( address_space_start, preload_reserve_start );
         }
     }