message: Add utility for generating wide temp
  Summary: As title.
diff: @@ -98,6 +98,12 @@ class IRCode {
  uint16_t allocate_temp() { return m_registers_size++; }
  + uint16_t allocate_wide_temp() {
  + uint16_t new_reg = m_registers_size;
  + m_registers_size += 2;
  + return new_reg;
  + }
  +
  /*
  * Find the subrange of load-param instructions. These instructions should
  * always be at the beginning of the method.
  