Turn LoadIndexedInterceptor into a Turbofan stub

src/compiler/code-stub-assembler.cc

Index: src/compiler/code-stub-assembler.cc
diff --git a/src/compiler/code-stub-assembler.cc b/src/compiler/code-stub-assembler.cc
index c09cfa61a395f09b63065d21fe5556f51e129e36..2392a2660098cc6afadde68e1dd989d27275d132 100644
--- a/src/compiler/code-stub-assembler.cc
+++ b/src/compiler/code-stub-assembler.cc
@@ -221,6 +221,12 @@ Node* CodeStubAssembler::WordIsSmi(Node* a) {
                    IntPtrConstant(0));
 }
 
+Node* CodeStubAssembler::WordIsPositiveSmi(Node* a) {
+  return WordEqual(
+      raw_assembler_->WordAnd(a, IntPtrConstant(kSmiTagMask | kSmiSignMask)),
+      IntPtrConstant(0));
+}
+
 Node* CodeStubAssembler::LoadBufferObject(Node* buffer, int offset,
                                           MachineType rep) {
   return raw_assembler_->Load(rep, buffer, IntPtrConstant(offset));