Add mul goldilocks

[starkoracles]

  0.000 (0.000): Prover::writeInput> size: 8
  0.000 (0.000):   write_word: 0x00000010
  0.000 (0.000):   write_word: 0x00000000
  0.000 (0.000): Prover::writeInput> size: 8
  0.000 (0.000):   write_word: 0x0000000a
  0.000 (0.000):   write_word: 0x00000000
  0.001 (0.001): image.size() = 7943
  0.001 (0.000): numSteps = 8192
  0.001 (0.000): Prover::onInit>
  0.010 (0.008): EXPANDING!
  0.012 (0.002): MemoryHandler::onWrite> GPIO_SendReceive, channel 0 size=0
  0.012 (0.000): IoHandler::InitialInput, 16 bytes
  0.012 (0.000): MemoryHandler::onWrite> GPIO_SendReceive, host replied with 16 bytes
  0.015 (0.002): MemoryHandler::onWrite> GPIO_MUL
  0.015 (0.000): Input[0x00]: 0x00a00004 -> 0x00000000
  0.015 (0.000): Input[0x01]: 0x00a00008 -> 0x10000000
  0.015 (0.000): Input[0x02]: 0x00a0000c -> 0x00000000
  0.015 (0.000): Input[0x03]: 0x00a00010 -> 0x0a000000
  0.015 (0.000): Output[0x00]: 0x00a00018 <- 0x00a00000
  0.015 (0.000): Output[0x01]: 0x00a0001c <- 0x00000000
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Exception { what: "Invalid requireZero: final_cycle.cpp:31" }', starter/src/main.rs:147:32

The runner I've used is here: starkoracles/zkos#12