[cleanup] Remove instanceof cache.

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index 6d135061264fc2429e49258c1034d3ea0180f766..8b1494d2807a1d400a7b80c981a2a5220f33453d 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -1542,8 +1542,6 @@ void Heap::MarkCompactPrologue() {
 
   isolate_->compilation_cache()->MarkCompactPrologue();
 
-  CompletelyClearInstanceofCache();
-
   FlushNumberStringCache();
   ClearNormalizedMapCaches();
 }
@@ -2729,10 +2727,6 @@ void Heap::CreateInitialObjects() {
   // expanding the dictionary during bootstrapping.
   set_code_stubs(*UnseededNumberDictionary::New(isolate(), 128));
 
-  set_instanceof_cache_function(Smi::kZero);
-  set_instanceof_cache_map(Smi::kZero);
-  set_instanceof_cache_answer(Smi::kZero);
-
   {
     HandleScope scope(isolate());
 #define SYMBOL_INIT(name)                                              \
@@ -2927,9 +2921,6 @@ void Heap::CreateInitialObjects() {
 bool Heap::RootCanBeWrittenAfterInitialization(Heap::RootListIndex root_index) {
   switch (root_index) {
     case kNumberStringCacheRootIndex:
-    case kInstanceofCacheFunctionRootIndex:
-    case kInstanceofCacheMapRootIndex:
-    case kInstanceofCacheAnswerRootIndex:
     case kCodeStubsRootIndex:
     case kScriptListRootIndex:
     case kMaterializedObjectsRootIndex: