[compiler] Drop the CompareNilIC.

src/code-stubs-hydrogen.cc

Index: src/code-stubs-hydrogen.cc
diff --git a/src/code-stubs-hydrogen.cc b/src/code-stubs-hydrogen.cc
index 461baaa4e6d71447b186938e8bba55a87ec3f7e7..07177a277a091b40671e1d9acfab32a55d32cc7f 100644
--- a/src/code-stubs-hydrogen.cc
+++ b/src/code-stubs-hydrogen.cc
@@ -1419,31 +1419,6 @@ Handle<Code> InternalArrayNArgumentsConstructorStub::GenerateCode() {
 
 
 template <>
-HValue* CodeStubGraphBuilder<CompareNilICStub>::BuildCodeInitializedStub() {
-  Isolate* isolate = graph()->isolate();
-  CompareNilICStub* stub = casted_stub();
-  HIfContinuation continuation;
-  Handle<Map> sentinel_map(isolate->heap()->meta_map());
-  Type* type = stub->GetType(zone(), sentinel_map);
-  BuildCompareNil(GetParameter(0), type, &continuation, kEmbedMapsViaWeakCells);
-  IfBuilder if_nil(this, &continuation);
-  if_nil.Then();
-  if (continuation.IsFalseReachable()) {
-    if_nil.Else();
-    if_nil.Return(graph()->GetConstantFalse());
-  }
-  if_nil.End();
-  return continuation.IsTrueReachable() ? graph()->GetConstantTrue()
-                                        : graph()->GetConstantUndefined();
-}
-
-
-Handle<Code> CompareNilICStub::GenerateCode() {
-  return DoGenerateCode(this);
-}
-
-
-template <>
 HValue* CodeStubGraphBuilder<BinaryOpICStub>::BuildCodeInitializedStub() {
   BinaryOpICState state = casted_stub()->state();