MIDEAST DEBT-As Saudi bourse opens to foreigners, debt market beckons

* Corporate bond market reforms to follow stock market opening * Authorities want to change heavy reliance on bank loans * Regulator to ease approval process, develop securitisation * Government may resume issuing bonds, aiding corporate issues * Legal framework, extent of foreign appetite remain questions By Bernardo Vizcaino June 1 (Reuters) - As Saudi Arabian authorities prepare to open the stock market to direct foreign investment this month, they're laying plans for a fresh set of reforms: