MIPS: Check that external references are registered in the serializer.

Port r22896 (4e54978a)

BUG=
R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/444943002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22919 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips64/codegen-mips64.cc

@@ -989,6 +989,7 @@ void MathExpGenerator::EmitMathExp(MacroAssembler* masm,
   DCHECK(!temp1.is(temp3));
   DCHECK(!temp2.is(temp3));
   DCHECK(ExternalReference::math_exp_constants(0).address() != NULL);
+  DCHECK(!masm->serializer_enabled());  // External references not serializable.
 
   Label zero, infinity, done;
   __ li(temp3, Operand(ExternalReference::math_exp_constants(0)));