Allstate Corp. said Wednesday it plans to lay off 3,800 employees, or 7.5% of its workforce, as part of an ongoing restructuring plan. The Northbrook, Illinois-based insurer said the layoffs will primarily affect employees in claims, sales, service and support functions. The company said it also will close offices, but didn’t give specifics. Allstate (NYSE: ALL) said the layoffs are part of an ongoing multi-year growth plan to increase its “personal property-liability market share by expanding…