[stubs] Port LoadFunctionPrototypeStub to CSA

src/ic/x64/handler-compiler-x64.cc

Index: src/ic/x64/handler-compiler-x64.cc
diff --git a/src/ic/x64/handler-compiler-x64.cc b/src/ic/x64/handler-compiler-x64.cc
index 51d162fe814a643ea0cdb322535796f71408dabc..425ed4762e0d710e270d683726c5bf702f947efe 100644
--- a/src/ic/x64/handler-compiler-x64.cc
+++ b/src/ic/x64/handler-compiler-x64.cc
@@ -83,14 +83,6 @@ void PropertyHandlerCompiler::GenerateDictionaryNegativeLookup(
   __ DecrementCounter(counters->negative_lookups_miss(), 1);
 }
 
-void NamedLoadHandlerCompiler::GenerateLoadFunctionPrototype(
-    MacroAssembler* masm, Register receiver, Register result, Register scratch,
-    Label* miss_label) {
-  __ TryGetFunctionPrototype(receiver, result, miss_label);
-  if (!result.is(rax)) __ movp(rax, result);
-  __ ret(0);
-}
-
 static void CompileCallLoadPropertyWithInterceptor(
     MacroAssembler* masm, Register receiver, Register holder, Register name,
     Handle<JSObject> holder_obj, Runtime::FunctionId id) {