THE DEATH machine in Texas is ready to roll and got it's first taste last night. The Lone Star State is slated to execute four killers over the next two weeks. At 6:22 p.m. last night, Steven Michael Woods Jr., pictured left, took the journey to oblivion and lashing out: "You're not about to witness an execution. You are about to witness a murder." He maintained his innocence til the end in the brutal slayings of Ronald Whitehead, 21, and Bethena Brosz, 19, in 2001. Co-defendant 