Fix signed LEB128 decoder
Fix signed LEB128 decoder

abenkhadra/libelfin,abenkhadra/libelfin,abenkhadra/libelfin,aclements/libelfin,aclements/libelfin,tempbottle/libelfin,tempbottle/libelfin,aclements/libelfin,abenkhadra/libelfin,aclements/libelfin