CHICAGO — Arlington Heights trustees Monday kicked off a new phase of negotiations with the Chicago Bears by approving a pre-development agreement with the football club to guide a possible redevelopment of Arlington International Racecourse. The pre-development agreement does not make commitments to the football club, which has proposed a $5 billion stadium and mixed-use development for the 326-acre site. But it is the most concrete indication so far that the village does intend to move ahead with the project in collaboration with the team. Trustees took the final vote during its regular boar…