Savings and loan industry regulators at a Senate hearing Wednesday raised their estimate of what it will cost to resolve the crisis in the nation's thrift industry to $45 billion to $50 billion. Sen. Lawton Chiles, D-Fla., chairman of the Senate Budget Committee, called M. Danny Wall, chairman of the Federal Home Loan Bank Board, to testify on whether the Federal Savings and Loan Insurance Corp., which insures deposits in savings and loans, will need a taxpayer bailout. Wall said at an earlier briefing for reporters that a taxpayer bailout is "premature at this point."