MIDEAST STOCKS-Saudi shares fall before reform news; Zain up on refinancing

* Saudis expected to announced details of reforms * Zain Saudi up 10 pct daily limit on loan refinancing * UAE economic data support Dubai and Abu Dhabi shares * Dubai index rebounds from support on 100-day average * Egypt's non-oil business activity shrinks, hits shares By Celine Aswad DUBAI, June 5 (Reuters) - Saudi Arabia's stock market fell on Sunday the details of the kingdom's economic reforms are announced, but telecommunications operator Zain Saudi soared in response to a loan refinancin