MIPS: Followup 'Introduce BUILTIN_CALL_PAIR.'

src/mips64/simulator-mips64.cc

Index: src/mips64/simulator-mips64.cc
diff --git a/src/mips64/simulator-mips64.cc b/src/mips64/simulator-mips64.cc
index 4b610738471d0539b978d320fa061ef76c3bc704..01cf03569710549beed00120fa1b4632f50d09ff 100644
--- a/src/mips64/simulator-mips64.cc
+++ b/src/mips64/simulator-mips64.cc
@@ -2196,6 +2196,8 @@ void Simulator::SoftwareInterrupt(Instruction* instr) {
       *sim_result = result;
       set_register(v0, arg0);
     } else {
+      DCHECK(redirection->type() == ExternalReference::BUILTIN_CALL ||
+             redirection->type() == ExternalReference::BUILTIN_CALL_PAIR);
       SimulatorRuntimeCall target =
                   reinterpret_cast<SimulatorRuntimeCall>(external);
       if (::v8::internal::FLAG_trace_sim) {