[runtime] Remove the redundant %_IsObject intrinsic.

src/full-codegen/x87/full-codegen-x87.cc

Index: src/full-codegen/x87/full-codegen-x87.cc
diff --git a/src/full-codegen/x87/full-codegen-x87.cc b/src/full-codegen/x87/full-codegen-x87.cc
index db5e1f6d5f768124bf1f06987aa3b7f0550bc3cb..e40dcb305001d88cc03b31fdc2fe998831ff4e98 100644
--- a/src/full-codegen/x87/full-codegen-x87.cc
+++ b/src/full-codegen/x87/full-codegen-x87.cc
@@ -3255,38 +3255,6 @@ void FullCodeGenerator::EmitIsNonNegativeSmi(CallRuntime* expr) {
 }
 
 
-void FullCodeGenerator::EmitIsObject(CallRuntime* expr) {
-  ZoneList<Expression*>* args = expr->arguments();
-  DCHECK(args->length() == 1);
-
-  VisitForAccumulatorValue(args->at(0));
-
-  Label materialize_true, materialize_false;
-  Label* if_true = NULL;
-  Label* if_false = NULL;
-  Label* fall_through = NULL;
-  context()->PrepareTest(&materialize_true, &materialize_false,
-                         &if_true, &if_false, &fall_through);
-
-  __ JumpIfSmi(eax, if_false);
-  __ cmp(eax, isolate()->factory()->null_value());
-  __ j(equal, if_true);
-  __ mov(ebx, FieldOperand(eax, HeapObject::kMapOffset));
-  // Undetectable objects behave like undefined when tested with typeof.
-  __ movzx_b(ecx, FieldOperand(ebx, Map::kBitFieldOffset));
-  __ test(ecx, Immediate(1 << Map::kIsUndetectable));
-  __ j(not_zero, if_false);
-  __ movzx_b(ecx, FieldOperand(ebx, Map::kInstanceTypeOffset));
-  __ cmp(ecx, FIRST_NONCALLABLE_SPEC_OBJECT_TYPE);
-  __ j(below, if_false);
-  __ cmp(ecx, LAST_NONCALLABLE_SPEC_OBJECT_TYPE);
-  PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);
-  Split(below_equal, if_true, if_false, fall_through);
-
-  context()->Plug(if_true, if_false);
-}
-
-
 void FullCodeGenerator::EmitIsSpecObject(CallRuntime* expr) {
   ZoneList<Expression*>* args = expr->arguments();
   DCHECK(args->length() == 1);