The fate of Wal-Mart's prodigious expansion plans inwill soon lie in the hands of Gov. Arnold Schwarzenegger. The state Assembly recently passed Democratic-sponsored legislation that would require local communities to commission economic impact studies on all new retail outlets larger than 130,000 square feet, and retailers would have to dedicate at least 10 percent of floor space to grocery items before approval is granted. The legislation is expected to be ratified by the state Senate soon. After that, it will pass to Schwarzenegger for veto or validation. If he approves the measure, Wal-Mart could have a tough time getting authorization for the 40 Supercenters it plans to build in the state during the next five years.