[runtime] Remove the redundant %_IsObject intrinsic.

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 f9730c8e8e38718e9673dbb40d5fb12a9d60430c..806ce3c98d191567dad4f74686776c1818a27be6 100644
--- a/src/mips/lithium-mips.cc
+++ b/src/mips/lithium-mips.cc
@@ -175,13 +175,6 @@ void LCompareNumericAndBranch::PrintDataTo(StringStream* stream) {
 }
 
 
-void LIsObjectAndBranch::PrintDataTo(StringStream* stream) {
-  stream->Add("if is_object(");
-  value()->PrintTo(stream);
-  stream->Add(") then B%d else B%d", true_block_id(), false_block_id());
-}
-
-
 void LIsStringAndBranch::PrintDataTo(StringStream* stream) {
   stream->Add("if is_string(");
   value()->PrintTo(stream);
@@ -1723,14 +1716,6 @@ LInstruction* LChunkBuilder::DoCompareMinusZeroAndBranch(
 }
 
 
-LInstruction* LChunkBuilder::DoIsObjectAndBranch(HIsObjectAndBranch* instr) {
-  DCHECK(instr->value()->representation().IsTagged());
-  LOperand* temp = TempRegister();
-  return new(zone()) LIsObjectAndBranch(UseRegisterAtStart(instr->value()),
-                                        temp);
-}
-
-
 LInstruction* LChunkBuilder::DoIsStringAndBranch(HIsStringAndBranch* instr) {
   DCHECK(instr->value()->representation().IsTagged());
   LOperand* temp = TempRegister();