MGM Mirage executives said Thursday that the deal struck this week to finance completion of CityCenter marks a turning point for the company, which has been pushed to the edge of bankruptcy by the recession. The deal was the result of a months-long effort to persuade eight banks — across four time zones, with representatives speaking at least three languages — to immediately risk $1.8 billion on the massive project, which had been in serious doubt. “This has been a 24-7 job involving conference calls at three in the morning,” MGM Mirage CEO Jim Murren said Thursday.