[runtime] Remove the redundant %_IsObject intrinsic.

src/mips64/lithium-mips64.cc

Index: src/mips64/lithium-mips64.cc
diff --git a/src/mips64/lithium-mips64.cc b/src/mips64/lithium-mips64.cc
index f0d62a134c46c0e3512c1eac5d0822da492a5e33..2c7fbdff8a6617a7feacd915d7d3c01bb688393c 100644
--- a/src/mips64/lithium-mips64.cc
+++ b/src/mips64/lithium-mips64.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);
@@ -1729,14 +1722,6 @@ 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();