message: [XLA] Add kCbrt to hlo_cost_analysis as trascendental.
  It should have a cost similar to kSqrt.
diff: @@ -103,10 +103,11 @@ Status HloCostAnalysis::HandleElementwiseOp(
  // trascendental ops (tanh or exp).
  if (opcode == HloOpcode::kExp || opcode == HloOpcode::kLog ||
  opcode == HloOpcode::kLogistic || opcode == HloOpcode::kPower ||
  - opcode == HloOpcode::kSqrt || opcode == HloOpcode::kRsqrt ||
  - opcode == HloOpcode::kTanh || opcode == HloOpcode::kSin ||
  - opcode == HloOpcode::kCos || opcode == HloOpcode::kExpm1 ||
  - opcode == HloOpcode::kLog1p || opcode == HloOpcode::kAtan2) {
  + opcode == HloOpcode::kSqrt || opcode == HloOpcode::kCbrt ||
  + opcode == HloOpcode::kRsqrt || opcode == HloOpcode::kTanh ||
  + opcode == HloOpcode::kSin || opcode == HloOpcode::kCos ||
  + opcode == HloOpcode::kExpm1 || opcode == HloOpcode::kLog1p ||
  + opcode == HloOpcode::kAtan2) {
  current_properties_[kTranscendentalsKey] = computation_count;
  } else {
  // Note: transcendental operations are considered a separate category from
  