MIPS: Tiny improvement of register constraints in LClassOfTest instructions.

src/mips/lithium-mips.cc

Index: src/mips/lithium-mips.cc
diff --git a/src/mips/lithium-mips.cc b/src/mips/lithium-mips.cc
index b66b98f208ef3c72a0211f71539cf45b6dfd4e91..2c098fe77c140bbd95d7b26d2b1b5d67d2bdad1f 100644
--- a/src/mips/lithium-mips.cc
+++ b/src/mips/lithium-mips.cc
@@ -1554,7 +1554,7 @@ LInstruction* LChunkBuilder::DoHasCachedArrayIndexAndBranch(
 LInstruction* LChunkBuilder::DoClassOfTestAndBranch(
     HClassOfTestAndBranch* instr) {
   ASSERT(instr->value()->representation().IsTagged());
-  return new LClassOfTestAndBranch(UseTempRegister(instr->value()),
+  return new LClassOfTestAndBranch(UseRegister(instr->value()),
                                    TempRegister());
 }