Sept 3 (Reuters) - An index of Chinese high-yield issuers fell on Friday to its lowest level since May 2020 amid rising investor worries over credit risks surrounding heavily indebted property developer China Evergrande Group. The ICE BofA Asian Dollar High Yield Corporate China Issuer index fell to 380.550 points from 385.135 the day before. Evergrande this week promised potential buyers it will complete construction of their homes as a growing number of contractors file lawsuits or stop work as they seek overdue payments. (Reporting by Noel Randewich Editing by Chris Reese)