message: Print fused_instructions_computation() only when the instruction is fusion. Also, mark instructions as fused before they are potentially removed via unique pointers.
diff: @@ -377,9 +377,11 @@ bool MultiOutputFusion::Perform() {
  VLOG(1) << "Fuse!";
  VLOG(2) << "Before multi_output_fusion:";
  VLOG(2) << "instr1: " << instr1->ToString();
  + if (instr1->opcode() == HloOpcode::kFusion) {
  VLOG(2) << "\n"
  << instr1->fused_instructions_computation()->ToString(
  HloPrintOptions().set_indent_amount(1));
  + }
  VLOG(2) << "instr2: " << instr2->ToString();
  if (instr2->opcode() == HloOpcode::kFusion) {
  VLOG(2) << "\n"
  