[runtime] Remove the redundant %_IsObject intrinsic.

src/x64/lithium-x64.cc

Index: src/x64/lithium-x64.cc
diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index 1ffa31d2af5664e8101300b8dbd95987fa7a292f..382c11ce8626d43817b539c7a20418b46104c83f 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -181,13 +181,6 @@ 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);
@@ -1726,12 +1719,6 @@ LInstruction* LChunkBuilder::DoCompareMinusZeroAndBranch(
 }
 
 
-LInstruction* LChunkBuilder::DoIsObjectAndBranch(HIsObjectAndBranch* instr) {
-  DCHECK(instr->value()->representation().IsTagged());
-  return new(zone()) LIsObjectAndBranch(UseRegisterAtStart(instr->value()));
-}
-
-
 LInstruction* LChunkBuilder::DoIsStringAndBranch(HIsStringAndBranch* instr) {
   DCHECK(instr->value()->representation().IsTagged());
   LOperand* value = UseRegisterAtStart(instr->value());