cmake: Change `-E chdir` to pass through stdout/stderr directly

Use OUTPUT_PASSTHROUGH instead of OUTPUT_NORMAL in order to avoid
buffering the output just to re-print it.

Source/cmcmd.cxx

@@ -621,7 +621,7 @@ int cmcmd::ExecuteCMakeCommand(std::vector<std::string>& args)
       int retval = 0;
       int timeout = 0;
       if ( cmSystemTools::RunSingleCommand(command.c_str(), 0, 0, &retval,
-             directory.c_str(), cmSystemTools::OUTPUT_NORMAL, timeout) )
+             directory.c_str(), cmSystemTools::OUTPUT_PASSTHROUGH, timeout) )
         {
         return retval;
         }