The debug flag recv_no_log_write prohibits writes of redo log records for
modifying page data. The debug assertion was failing when fil_names_clear()
was writing the informative MLOG_FILE_NAME and MLOG_CHECKPOINT records
which do not modify any data.

log_reserve_and_open(), log_write_low(): Remove the debug assertion.

log_pad_current_log_block(), mtr_write_log(),
mtr_t::Command::prepare_write(): Add the debug assertion.